Blaahval

I have had this problem for a while and it is getting really annoying. My problem is that the current window freezes and I can't access anything. When I use alt + tab to go to another window and back, everything works fine again. This happens randomly, so I have no clue about whats causing it. It should be noted that this continues after severals formats of the drive, and I have just recently scanned for virusses and spyware. As far as I remember, the problem started when I changed to my current AMD64 processor. My current system is, AMD64 3000+ (Socket 939) Asus A8V Deluxe Powercolor Radeon 9700 Pro Maxtor Diamond 9 120 GB HDD 512 MB Kingston ValueRAM PC2700 Could this be a driver problem or something? I can't think of anything else. Thanks in advance.