Monitor timings. Look in your graphics card settings.
or if you actually want useful information, try posting your spec.
OK then.
Shuttle SN27P2
Geforce 7600 GS 256MB
AMD X2 64 4200+
2GB DDR2-800
Realtek 7.1 audio
Samsung LN-S4695D 46" 1080p LCD via DVI-> HDMI
I can't see any monitor timings to adjust that would help. But please advise based on that, if you can.