Yeah it's virus free. Haven't had a virus in quite some time.
I think I may just take it into a local computer shop and see what they make of it.
What virus scanner?
It sounds to me like a device isn't functioning like it should. It's most likely a driver issue.
I think you should update the drivers for each device. You might also want to clear up a lot of start-up entries that could interfere with 3D applications or hardware in general.
Also, what refresh rate is your monitor set to and what refresh rate are you trying to run these games at? Is it a CRT or an LCD monitor?