Yuck.

You aren't going to enjoy the 'fix' for this. You've had some sort of major hit to Windows.

Open it up in safe mode and reinstall Windows. If it STILL does this, then you have to reinstall Windows to a new directory. This will, however, lose track of where your programs are (they're still there, but Windows can't find the pointers.)

Run the reinstall first and if you have problems, check back here and tell us about them. I'll try to keep an eye on this place and give you what help I can.