Lost OS Access


New Member
I've been in dual boot hell for a couple of days here. I'm developing a device driver for a customer. The system I'm using had Win 7 installed when I got it and I set it up XP as a second boot option. I haven't worked much with Vista or 7, but came across EasyBCD as an option to do a dual boot. As part of the process with development, I need to go into safe mode with XP to fix things and I have been unable to get in. I tried setting XP as the default boot and hammered F8 the millisecond the menu came up with no luck. Then I tired switching to Win 7 default to change to it only to find when the system rebooted, the only two choices on the menu were both Win 7! XP was gone. I had EasyBCD installed under XP. I guess my only option at that point was to boot into Win 7, install EasyBCD there and now the boot menu shows three choices, two Win 7 and an XP. I think this is an artifact of the two installations of EasyBCD. The installation under XP now shows Win 7 and XP, but both point to drive E, which is the Win 7 drive under XP. I think the changing the OSs to both be Win 7 when you change the boot order is a bug. It is not expected behavior and I think the list of boot options still said XP was on the list when I shut down EasyBCD and rebooted (though I am not 100% sure because I wasn't looking for it.) The menu text according to the Edit Boot Menu setting on the XP side is: Windows 7 Professional Default Microsoft Windows XP Though it showed up as Windows 7 Professional Windows 7 Professional When I booted. Yesterday I broke things pretty badly when trying to get into safe mode in XP and had to repair both installations numerous times before I finally got it to work as a dual boot again. Dual boot used to be a no brainer before Vista, why did Microsoft break it? Bill
The BCD does not point to the XP drive, it points to copies of the XP boot files in the "system" partition.
MS designs the dual-boot to work automatically in a normal chronology. i.e new system installed after older system.
If you choose to add an old OS on top of a newer one, there is no backwards compatibility so no automatic dual-boot will occur, and XP will take over the boot process without knowledge of the existence of Vista/7.
With EasyBCD 1, the end user had to repair the Vista/7 boot and manually copy XP boot files to the correct location, then edit the copied boot.ini to reflect the change of location.
Unfortunately the information necessary to do this correctly was not available through system software, or by intuition or experience, involving knowledge of BIOS and MBR partition table information, so the process was very much "suck it and see" until the right combination was found by serendipity.
With EasyBCD 2.0, the code to find that elusive information was included, and everything is done for you automatically, including the ability to multi-XP from a single menu, impossible by normal means using the Vista/7 bootmgr.
That doesn't stop the end-user from subsequently messing up the boot by mistakenly thinking that EasyBCD is pointing to the wrong place.
The XP extended boot menu is entered by an interrupt to the MS NTLDR code with F8.
The Vista/7 ext boot menu is entered by an interrupt to the MS bootmgr code with F8.
The key point is that you must interrupt the correct code at the early point of its execution.
bootmgr chains NTLDR when you select XP from the BCD, so you must hit F8 as you start booting if you want to get the Vista ext menu, but you must wait for the boot menu, select XP, THEN start tapping F8 to reach the XP ext menu.
Please refer to the sticky thread for links to useful information about dual-booting and to this link for the detail of how XP is handled