The same happened to me yesterday
I have the same problem. Now when I restart my computer it doesn't load correctly, I only get the wallpaper image and the mouse cursor, but nothing to click on. I tried using the windows CDs, but the choices I get (reinstalling windoes or repairing windows don't help). When I choose repairing I get the DOS mode but I don't have any idea what do do.
The only possibility to do anything is using the windows task manager. With it I treid resetting windows to an earlier date, but that doesn't solve the problem at all. I checked my computer with Norton Antivirus, but it couldn't detect any viruses.
Do you know ho I can solve the problem without having to format my drive and reinstall windows?