And your using the latest powercolor XP drivers?
Does your monitor show up in the device manager or does it just show a plug n play monitor listing?
For poops and giggles try this:
1. Click on start, then run.
2. Type DXDIAG and click on OK.
3. Click on the "Sound" tab.
4. Under DirectX Features, move the slider bar next to Hardware Sound Acceleration Level to the right so that it is set to "Basic acceleration".
Saw this for one game FAQ:
"Why do I have wavy lines across my screen when I play the game?
We have found this to be the case when outdated DirectX drivers are present on a system."
Ummm I guess also you can try underclocking it some to see if its a voltage problem. If none of this works, Id get it swapped out.
Hope this helps.
Your bargaining posture is highly dubious.