Find boot disc of any kind. (make sure it is bootable) and restart the computer hit any key when you get the message "press any key to boot from...
also download CCleaner delete temp files (this is safer then deleting eveyryhing in the temp directory. )
Try a System Restore to the time before it happened. Or boot off of the Vista DVD and chooe to Repair Windows. It could be because of malware....
Separate names with a comma.
