I formatted my pc to.Whats your graphics card
Try checking for updates or reinstall graphics drivers
Actually i always keep updates in date so problem is from update?Did you by any chance update to the newest Catalyst Drivers (12.4)? I just did today and I'm getting the same kind of artifacts at least in TF2. I'm rolling back now to 12.3. I'll post how it turned out when its done. If you need a link to it:
http://support.amd.com/us/gpudownload/windows/previous/12/Pages/radeon.aspx?os=Windows Vista - 64-Bit Edition&rev=12.3
Actually i always keep updates in date so problem is from update?