Problem with NVIDIA as well as ATI graphics card

I'm having problems with the config of my signature. The problem is the following:
- Black screen displays of white-colored immediately if I run a game.
- Black screen random when playing movie.

So I suspect my great graphics card to be dead. A friend lends me then a Radeon HD3850.

And here I have a problem when installing the ATI drivers. During installation, the installer tells me that the drivers are not compatible with the card (made installation mode fails). I have selected the Catalyst 9.3 AMD site (for winxp).

My question is this is it possible that eventually the problem comes from the power supply? Or is there a conflict with the change of a graphics card nvidia to ATI? (I uninstalled the nvidia drivers in "add remove programs")?

The utility Add/Remove programs, it is not always top, especially for a passage NVIDIA -> ATI (or vice versa)

Uninstall the drivers NVIDIA and ATI with Driver Cleaner Pro. Reboot and reinstall your HD 3850 with Catalyst.

After that, it could be power supply or something else begins by removing the graphics card from the list of suspects

Totally agree. I will first do the household with the driver

Never had a problem uninstalling the driver in the classic way of a change of graphics card. Worse, I sometimes do not even uninstall the old driver without hassle.

Yes, but you, you are a great patient!

problems related to the change in graphics card, it's so common!

as said before, a nice cleaning, and installation of the following happens the better.

otherwise, after install of your video card, reinstall DirectX, it will not hurt