Video Problems with NVidia GE 4 Dell 8200

[mivate]

My computer video displays crazy flickers and colors...so badly that I cant make out anything on my computer. The problems began when I upgraded to Win XP for my Dell 8200 which has a GE Force 4 graphics card, originally the screen would only work with standard VGA driver, and I tried several versions of NVidia drivers and even updated my BIOS...after I installed the latest Nvidia driver per their tech support I got crazy colors, dots, flickers etc....it happens even in BIOS..safe mode etc...the funny thing I noticed if I unplug the power, the monitor works for about 30seconds until it starts to get crazy and then it just gets worst and worst...the garble is not consistent

I have even tried to a re-format with windows cd but even that cant complete cause after 30seconds the screen becomes unreadable...

I have taked apart my computer and check the card and re-installed it fine..still the problem persists..anyone have any idea?

PS - I know its not my monitor as it works fine with other computers and also I have tried hooking up my computer to other monitors and the problem is the same...

thanks in advance!