Important Reinstalling the Windows operating system or performing an in-place upgrade of your operating system is an extreme troubleshooting step that you should only take if you fully understand the ramifications and risks involved. If you decide to take this step, make sure that you have the original Windows XP installation media and product key that was included with your operating system. If you are not comfortable trying to reinstall or repair the Windows operating system, you might want to contact your computer manufacturer for help or bring your computer to a professional repair shop.
This article describes two methods to perform an in-place upgrade (reinstallation) of Windows XP. If you reached this article expecting to find other information, please use the search box at the top of this page to find more appropriate content to resolve your issue.
An in-place upgrade is also named a repair installation. This operation reinstalls Windows XP to the same folder on your computer where it was originally installed. You may want to perform an in-place upgrade if your installation of Windows XP must be repaired and if one of the following conditions is true:
- You cannot start Windows XP in safe mode. For more information about how to start your Windows XP-based computer in safe mode, click the following article number to view the article in the Microsoft Knowledge Base:
315222 A description of the Safe Mode Boot options in Windows XP
- You cannot start Windows XP after you install a Microsoft software update.
- There is a registry problem that cannot be solved by using other tools such as System Restore. For more information about System Restore, click the following article number to view the article in the Microsoft Knowledge Base:
306084 How to restore the operating system to a previous state in Windows XP
- You must apply default (file and registry) permissions to your Windows XP installation. This condition can occur if program files are missing or damaged after you make changes or updates to your computer or programs.
- You must register COM components and Windows File Protection (WFP) files. This condition occurs because of missing or damaged system files.
- You must use the Windows Setup program to enumerate Plug and Play devices again. This includes the hardware abstraction layer (HAL).
This content is designed for an intermediate to an advanced computer user. There are several links in this article that take you to other articles with additional information. You might find it easier to follow the steps if you print this article first.
Before you start a reinstallation, please review these troubleshooting articles and review the following “When you should not reinstall” section to determine whether the reinstallation is necessary.
If you feel comfortable about performing the troubleshooting, review the following Microsoft Knowledge Base articles before you start the reinstallation:
If you are not comfortable about performing the troubleshooting, you can continue to the next section, or you might want to ask someone for help or contact Microsoft Support.
When you should not reinstall
A reinstallation may not resolve the problem that you are experiencing. Please review this section to see whether a reinstallation is appropriate for your situation.
Repair a component
Do not perform a reinstallation to repair a component or program that is currently not installed. If you have the necessary permissions, use the Add or Remove Programs item in Control Panel, or reinstall the component or program instead of Windows. To open Add or Remove Programs in Windows XP, click Start, click Control Panel, and then click Add or Remove Programs.
User account problem
Do not perform a reinstallation to try to resolve a problem with a user account, password, or local profile. To determine whether the problem is related to a user account, password, or local profile, create another user account (if you have the required permissions), and then log on to that account to see whether the problem is resolved. For more information about creating a new user account in Windows XP, click the following article number to view the article in the Microsoft Knowledge Base:
If you reinstall Windows XP, all existing restore points are removed and a new system checkpoint restore point is created after the reinstallation is completed. Do not perform a reinstallation if you may have to use System Restore to restore your computer to a previous state. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
Do not reinstall to resolve a problem with third-party programs, files, or registry entries. Contact the manufacturer of the third-party program to resolve any problems.
Do not reinstall if you suspect hard disk problems. For more information about checking for disk errors, click the following article numbers to view the articles in the Microsoft Knowledge Base:
You can also contact the computer manufacturer for more information about how to troubleshoot hard disk problems.
Do not reinstall if you suspect a problem with a third-party device. Determine whether the latest device drivers are currently installed for the device. Contact the manufacturer of the third-party device to resolve any problems.
If after reviewing this section, you must reinstall Windows XP, continue to the next section.
Before you reinstall Windows XP
Review the following topics before you reinstall Windows XP. These topics present lots of information and may seem complex, but reading this information will help you understand clearly what you need and what you must do before reinstalling Windows XP.
Windows Installation CD
Before you start, have your Windows installation CD and the product key available. Without these, you cannot reinstall Windows. If Windows was preinstalled on your computer, contact the computer manufacturer for help in obtaining the Windows installation files and product key.
Many of the device drivers for your hardware components are integrated into Windows. However, devices such as printers, monitors, graphic cards, sound cards, modems, external drives, and scanners usually have separate installation CDs. If you do not have all the drivers for your hardware components, you can download the drivers from the Internet and then write them to a CD.
If your computer requires a third-party mass storage device driver or hardware abstraction layer (HAL), make sure that you have a copy of the files on a separate storage media before you start the reinstallation.
Internet Explorer 7
If Internet Explorer 7 is installed on your computer, you must uninstall it before you reinstall Windows XP. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
Collect and store the CDs and product keys for your programs in an appropriate location so that you can reinstall the programs after you have reinstalled Windows. These programs may include the following:
- Microsoft Office programs
- Antivirus software
- CD writing software
- Internet Provider software
Before you reinstall Windows, back up all important data to another location. Data that you may want to back up could include the following:
- My Documents (documents, pictures, music, videos)
- Program folders (configuration data, user data)
- Address books
- E-mail messages
- Document templates
The original backup copies of your registry files (located in the %systemroot%\Repair folder) are replaced when the reinstallation is completed. These original registry files in the Repair folder were created either when you started Windows XP or when you last used the Backup utility to back up the system state. If you think that you might have to use the registry backups after the reinstallation is complete, copy these registry backup files to another location before you perform the reinstallation.
You can restore certain network settings after you reinstall Windows. Before you start the reinstallation, record your computer’s network settings so that they can easily be available if this step is required. These settings include the following:
- Computer name
- Workgroup or domain
- TCP/IP settings
To find these settings, do the following steps:
- To find these settings, click Start and then click Run.
- Type control ncpa.cpl in the Open text field and then click OK.
- Right-click Local Area Connection and then right-click Properties.
- Record the network settings.
Internet provider information
To make sure that you can reconnect to the Internet after you have reinstalled Windows, record your Internet provider information. This includes user name, password information, and names of mail servers.
Warning This procedure may involve changing your CMOS (Complementary Metal Oxide Semiconductor) settings and changing your Basic Input/Output System (BIOS). Incorrect changes to the BIOS of your computer can result in serious problems. Microsoft cannot guarantee that problems that result from changes to your BIOS can be solved. Change your CMOS settings at your own risk. Incorrect or corrupted CMOS and BIOS settings can cause startup problems or shutdown problems.
If you must adjust the BIOS startup sequence of your computer so that it can start from the installation CD, the sequence should be in the following order:
- CD drive
- Hard disk
- Floppy disk drive
During startup, BIOS searches for a disk that has an operating system it can load. On a computer that has an operating system installed, this is usually the hard disk. The BIOS is configured to search disks on the computer in a certain order, called the startup sequence. If the computer hard disk is configured in the BIOS as the first disk in the startup sequence, the computer starts by using the hard disk and does not search the CD drive for a startup disk.
To configure the BIOS to search the CD drive for a startup disk before it searches the hard disk, follow these steps:
- Restart your computer.
- When the computer first starts, it performs the power-on self test (POST). This test checks that all connected devices are functioning. As part of the POST, the memory is checked. During the memory test, a message will appear that tells you how to access the BIOS. For example, you may see the following message or a similar message that explains how to start the BIOS setup:
PRESS DEL TO ENTER SETUP
In this example, you must press the DEL key immediately after the memory test is finished to start the setup process. You may have to press the key several times to make sure that you access the BIOS setup.
Tip There are other keys that may provide access to the BIOS. They include the following:
If you are not sure how to access the BIOS setup, see the user manual for your computer’s motherboard.
- Look for the startup sequence settings (also known as boot sequence or boot order). You can usually use the arrow keys to move through the menus and settings.
- When you find the startup sequence setting, you can usually press ENTER to modify it. Press the PLUS SIGN (+) or MINUS SIGN (-) key until the CD drive is selected as the startup disk.Tip More information about how to modify the BIOS can be found in your user manual. It usually contains descriptions of the menus and instructions on how to modify the options. The BIOS itself usually contains context-sensitive Help with the individual steps.
- As soon as you have specified the CD drive as the first location to search for a startup disk, you can usually press ESC to return to the menus. In the main menu, select the option SAVE AND EXIT SETUP or a similar option. When the confirmation SAVE TO CMOS AND EXIT or a similar option appears, select YES.
- If you cannot select YES, type the letter y.Note BIOS uses a QWERTY keyboard layout. If your keyboard settings follow a different layout, you will have to press the Y key as it appears on a QWERTY keyboard.
- After you exit the BIOS setup, your computer will restart.
- Make sure that the computer starts by using the CD drive. Insert the Windows XP installation CD and restart the computer. If this is successful, you can start reinstalling Windows XP.
If you are not comfortable trying to perform this task, you may want to ask someone whom you know for help. Or you may want to contact Microsoft Support to help you resolve this issue.
Windows XP preinstalled
If Windows XP was preinstalled on your computer, view the following article before you continue with reinstallation:
Note If Windows XP was preinstalled on your computer, you may not have the Repair option that you may require during the reinstallation process. Contact your computer manufacturer to make sure that you have the installation CD for a repair install.
Windows XP Service Pack 2
If Windows XP Service Pack 2 (SP2) is already installed on your computer, you must reinstall SP2 after you reinstall Windows XP. One way to do this is to combine the SP2 files with the Windows XP files and reinstall them at the same time. Follow the links in this section to try this method.
Note There are also two methods to reinstall SP2 separately after you have reinstalled Windows XP. You can find those two methods in the “After you reinstall Windows XP” section.
Note Service packs are cumulative. Each new service pack contains all the fixes that are included with earlier service packs and any new fixes. You do not have to install an earlier version of a service pack before you install the latest version. For example, you only have to install Windows XP Service Pack 2 (SP2), you do not have to install Windows XP Service Pack 1a (SP1a).
Reinstall Windows XP
To reinstall Windows XP, try either of the following methods. If the first method does not work, try the second.
Note You may want to disconnect from the Internet during the installation. This helps protect you from malicious users.
Method 1: Start the reinstallation from Windows XP
To reinstall Windows XP by using Windows XP CD, follow these steps:
- Start your computer.
- Insert the Windows XP CD in your computer’s CD drive or DVD drive.
- On the Welcome to Windows XP page, click Install Windows XP.
- On the Welcome to Windows Setup page, click Upgrade (Recommended) in the Installation Type box (if it is not already selected), and then click Next.
- On the License Agreement page, click I accept this agreement, and then click Next.
- On the Your Product Key page, type the 25-character product key in the Product key boxes, and then click Next.
- On the Get Updated Setup Files page, select the option that you want, and then click Next.
- Follow the instructions that appear on the screen to reinstall Windows XP.
If you successfully completed the reinstallation, congratulations. You are almost done. Please continue to the “After you reinstall Windows XP” section to finish.
If you received an error or if the reinstallation did not finish, try method 2.
Method 2: Repair install of Windows XP by starting your computer from the Windows XP CD
Note If Windows XP was preinstalled on your computer, you may need the installation CD to reinstall. Contact your computer manufacturer to make sure that you have the installation CD for a repair installation.
To reinstall Windows XP by starting your computer from the Windows XP CD, follow these steps:
- Insert the Windows XP CD into your computer’s CD drive or DVD drive, and then restart your computer.
- When you receive the “Press any key to boot from CD” message on the screen, press a key to start your computer from the Windows XP CD.
- The following message on the Welcome to Setup screen will appear:
- Press ENTER to set up Windows XP.
- On the Windows XP Licensing Agreement screen, press F8 to agree to the license agreement.
- Make sure that your current installation of Windows XP is selected in the box, and then press R to repair Windows XP.
- Follow the instructions that appear on the screen to reinstall Windows XP. After you repair Windows XP, you may have to reactivate your copy of Windows XP. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
310064 How to troubleshoot Windows XP Setup problems when you upgrade from Windows 98 or Windows Millennium Edition
If you successfully completed the reinstallation, congratulations. You are almost done. Please continue to the “After you reinstall Windows XP” section to finish.
If you received an error or if the reinstallation did not finish, unfortunately, this article did not resolve your problem. For your next steps, you may want to ask someone whom you know for help. Or, you may want to contact Microsoft Support to help you resolve this problem.
After you reinstall Windows XP
After you finish the reinstallation, complete the following final tasks.
Note You may also want to enable the firewall in Internet Explorer. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
Reinstall Windows XP Service Pack 2
If Windows XP Service Pack 2 (SP2) was installed on your computer before you reinstalled Windows XP, you must reinstall SP2. If you did not already reinstall SP2 with the Windows XP in the previous section, use one of the following methods to reinstall SP2 now.
Method 1: Use the service pack CD and reinstall the service pack after you reinstall Windows XP
Method 2: Download the service pack after you reinstall Windows XP
For more information, click the following article number to view the article in the Microsoft Knowledge Base:
Reinstall all updates to Windows
After you reinstall Windows XP, you must reinstall all updates to Windows also. To reinstall Windows updates, visit the following Microsoft Web site:
Reinstall Internet Explorer 7
When Windows XP is repaired and is running correctly, reinstall Internet Explorer 7. To do this, you will need the Internet Explorer 7 installation package. This package is available through Windows Update. Also, the package may still be on the computer from the first time that you installed Internet Explorer 7. Locate the installation package in the folder in which you saved the files, and reinstall the program.
Note This package may be located in the Temporary Internet Files folder. If you cannot locate the Internet Explorer 7 installation package, visit the following Microsoft Web site to obtain this package:
To connect to the Microsoft download site, you must have a functional Web browser. If Internet Explorer 6 does not work on the computer after you uninstall Internet Explorer 7, you cannot download the Internet Explorer 7 installation package. In this situation, you can use a computer that has a functional Web browser to download the Internet Explorer 7 installation package. Then, use a shared network drive to install the program onto the repaired computer. If you cannot use a shared network for this purpose, copy the Internet Explorer 7 installation package onto a CD, and install Internet Explorer 7 on the repaired computer from the CD.
If you had difficulty completing these final steps, unfortunately, this content is unable to help you any further. So, you might want to ask someone for help, or you might want to contact Support.