Radeon9800pro 128

Help
I just built a new system based around a Asus p5p800 mobo, intel p4 3.4 processor, 1 gig ram some my old components and the above vid card. Now everything seemed to be going fine until I crashed a coouple times in Doom3 and Halflife2 with the supplied drivers.
So what do I do like good little tard but go to ati's site and download the latest divers and install them. This is where my troubles began in any other colour the True I get dots appearing in my windows desktop as well as 3d games if they start at all. I have since tried uninstalling and going back to the factory drivers with the same results. If I just use the xp drivers I can use any colour scheme with no problems so I don't think the card is F'd. I downloaded the beta Omeaga drivers same problem. I don't have Pci devices in slot 1 or 5. The mobo manual tells me agp is shared with usb ports 1 though 4 could this be a problem? I also discovered that my 9800 is actually being detected as residing in pci bus1, device 0, function 0 , now when i try to force it with the omega adapter software to agp4 or 8 I restart and its still back on the pci bus.
I read some where that I might need to reinstal xp is this nescasary or can I do a repair.
Thanks I am at my wits end here...Randy

First things first

Have you installed the chipset drivers (for your motherboard)... If the card is working in PCI mode the chipset drivers should fix that

As for graphics corruption - are you sure that the fan on the heatsink is spinning OK and that the heatsink itself is securely mounted? Are you using the stock cooling or have you recently replaced it with something else... If so what, when and are you sure it's not touching anything it shouldn't be?

Sounds like it could be overheating...
What are you are your temps?

The chipset drivers are installed the card seems to be working in agp8 according to the omega software same problem persists however. How do I check temp? I am running it with factory fans in a Antec mid tower. No cards are installed below it and the fan is working. If it was an overhaeting problem why does it work perfectly fine at 1024x768 in 32bit and this is in 2d desktop mode I am also using only the radeon on the power pass through.