There’s a section of the EasyBCD documentation/user manual/wiki that contains more than just information on how to use the program. If you’ve corrupted your bootloader, run into one or more bootmgr-related errors, installed Windows XP or Linux after installing Vista, or otherwise managed to fry, crack, melt, or break the Vista bootloader, then here’s how you fix it.
We’ve compiled information from over twos-years’ worth of experience with fixing broken bootloaders into a single guide, broken up into subsections for varying levels of damage to the bootloader. If you can get into Windows, we advise that you download & install EasyBCD, then follow the instructions in this section of the guide to repair the Vista bootloader from within Windows.
If your bootloader is so damaged that you cannot get into a Windows operating system, then get your Windows Vista DVD out and boot from it. If you don’t have a Windows Vista DVD, grab a copy of our Windows Vista Recovery DVD instead, stick it in your CD-ROM drive, and prepare to boot from it.
To repair the Windows Vista bootloader once you’ve booted from the Windows Vista DVD/Recovery CD, just follow the instructions here: Recovering the Windows Vista Bootloader From the DVD to get your problem sorted-out.
Whether you choose to recover from within Windows with the help of EasyBCD or by booting from the CD/DVD, you’ll have several options of what to do next. If all what you did was install another OS after installing Vista (such as GRUB overwriting the Vista bootloader, or the Windows XP NTLDR bootloader taking over the MBR and deleting the Vista bootloader), reinstall the bootloader to the MBR and/or bootsector by following the appropriate instructions.
But if your BCD registry has modified and is now missing entries or contains invalid references, you’ll have to take more serious measures. You can try to have EasyBCD reset your BCD data to a clean slate and then add the entries you need or have Windows Vista’s recovery center attempt to locate any missing Windows Vista installations on your hard drive.
Sometimes, though, that’s not good enough. If the BCD registry isn’t just incomplete or incorrect and is instead corrupted or damaged, you’ll have to delete the registry (nuke it) and start from scratch. This is easy with EasyBCD, thanks to the “Recreate BCD Registry” option; but when booting from the Vista DVD it is a
slightly much more involved procedure that involves manually delving into the bcdedit.exe, bootrec.exe, and bootsect.exe commands.
Whatever your problem; no matter if it’s a simple matter of a misplaced MBR or a corrupted BCD registry, you should be able to repair the Windows Vista bootloader by following one of the two instruction sets on this page.