Have you tried running CS in Win9x emulation? If you haven't you can do this by right-clicking on the shortcut to CS, going to Properties, and the Compatibility tab. Under this, enable compatibility mode for Windows 98/ME, and also check "disable visual themes" at the bottom. Hit OK, and try it out. If this doesn't help, try switching the video mode from within CS from OpenGL to Direct3D or vice versa.