I resently installed SP2 for Windows Xp and i had a problem with my computer a couple days later and so I did a system restore. Without thinking I set my computer back 5 days not thinking that I installed SP2. When the computer restarted after doing the system restore it says windows was not sure which startup i used last and i chose start windows normal and it flashed a blue screen then restarted and then went back to the windows was not sure which startup last used. Ive tried all the startups and I get the same error. Please help.

Ouch! It sounds like you're probably going to have to do a repair install. To do that, boot to your original XP install disk when the setup asks if you want to repair your windows Installation reply "No" and proceed like you are going to install Windows XP just before the Install actually starts, the setup program will say "Looking for other Windows Installations" when it finds your existing install, it will ask if you want to repair this installation or install. At THIS point respond that you want to repair. The setup program will proceed and replace all the XP windows files, but will keep your application installations intact. When the install is complete, you'll need to reapply all service packs. This works well in most cases of corrupt xp installations.