So I went along with my plan to install Windows XP on the secondary partition of my laptop's harddrive, so I could play older OpenGL games(KotOR was the tipping point). It works great, all the old games run flawlessly. There's just one problem. I can no longer boot into Windows 7. The OS and all it's stuff is still there on the primary partition, but Windows XP seems to have taken over booting and now I can only boot into that OS. I already tried renaming the boot.ini so it would default to the primary partition, but that failed rather abysmally, and I had to restore the file using a linux live CD. Is there any easy way to fix this so I can boot into either Windows 7 /or/ Windows XP? If I boot up with the Windows 7 install DVD will its repair function get me back into 7, while still allowing me to switch to XP when I want to run older games? Does it matter that the windows 7 I have is 64 bit and the Windows XP I installed on the second partition is 32 bit(so that 16-bit installers from windows 95/98 would work)? Please help.

The XP bootloader isn't capable of loading anything newer than XP, so when it installed its bootloader, it wiped the one for 7. You can use the bootrec utility from a Windows install disc to restore the needed bootloader, then use bcdedit to add an entry for XP.

I figured it was something like that. Ok thanks, I'll give that a try and let you know how it works.

EDIT- I ran a recovery disc and used it's startup repair tool. That got me back into Windows 7. However, I have no idea how to add Windows XP to my bcd, using bcdedit or otherwise. I'm gonna google that now.

EDIT2- this article explains how:
http://www.kombitz.com/2009/01/13/how-to-add-windows-xp-to-windows-7-boot-manager/

I'll let you guys know if it works.

EDIT3- Nope. I have both listed now, but when I select "Windows XP" it tells me it cannot find "/ntldr". What's more, I now have Windows 7 telling me it's not genuine anymore, so I have to fix that now too.

EDIT4- fixed. I just had to copy over the NTLDR and NTDetect.com files from the i386 directory of the Windows XP CD. This can be done from the recovery console but I just did it from Windows 7. Now both OS's are booting correctly. Thanks for pointing me in the right direction Tari.