In addition to what Ken has suggested (and I've seen monitors go pink,
green and blue before failing), try knocking your display settings down a
notch. If using 32 bit color, try 24. If using 24, try 32 bit. Oddly with
some of the newer hardware 24 bit color can be more work to produce than 32
bit. Also, check that your desktop settings and refresh rates are within
the limits recommended for *both* the display adapter and the monitor.