Can’t boot WinXP AFTR re-installin Win2k

I had to re-install Win2k Pro, after having set up WinXP Pro RC2. Now I get an error when trying to boot back into XP: *Windows 2000 could not start because following file is missing or corrupt: \WINXPPRO\SYSTEM32\CONFIG\SYSTEM startup options for Windows 2000, press f8″. I don’t have an ERD (Duh on my part), and running repair doesn’t see the WinXP directory. Any thoughts?