New Hardware Found Bluescreen

[lifelost1]

My friend bought an 8600 for his Dell XPS 400. He took out his old 7300 and put in the 8600 without uninstalling drivers. As soon as it found the hardware it bluescreened everytime. I told him to uninstall the drivers for the 7300 then try to install the drivers for the 8600. It still bluescreened at found new hardware. So we switched the 8600 out with the 7300 and then it bluescreens at found new hardware on that card. We have started it in safe mode and tried to see if we could install drivers but it blue screened once it found the hardware. The only thing I know of to do now is to either maybe try it out with a pci card instead of pci e, or reinstall windows.

If I do have to reinstall windows can I install it on another hard drive and when its working hook up his old hard drive so I can save the data on the hard drive? I know programs installed on the old hard drive wont work but I will still be able to get to the files right?

Can anyone help me?
Thanks

Im pretty sure his specs are
XPS 400
intel Pentium D @ 2.8
1 GB of ddr SDRAM
375 watt power
Internal Sound

 

[techgeek]

Boot into Safe Mode with networking. Download Driver Cleaner Pro. Install it. Next uninstall the nVidia drivers. It should ask you to reboot, do so. Again go into Safe Mode and run Driver Cleaner, run the nVidia script. This should remove all traces of your old driver from your system. Then reboot into Normal Mode. If all is well you should be presented with the Found New Hardware dialog. Cancel that and install the new driver.