This can be caused by driver conflicts with the games. Test your drivers using DXDiag: Click Start--> Run-->DXDIAG
Click the "Test" buttons in the Display, Sound, and Music tabs.
Has your machine changed since before this happened till now? Updated drivers for video, keyboard or DirectX...stuff like that.
You say "though I sometimes have some spyware that I have to restart the computer to get rid of." You do have the spyware program delete the spyware first, right? Just booting will not get rid of the spyware.
Hope this gives you some ideas of what to look for.