So you currently have a dual boot system if I am understanding right? Have you tried a repair on the Windows 2000 OS? I know you just did the XP repair, but how about the 2000?It shouldnt be that sensative. Is everything cool with your BOOT.INI file?
Can you boot the Windows 2000 install in safe mode? Then you can do a driver roll back and see if that clears the problem for you.