Properly replacing ati card with nvidia

With the old card in, just go to the add-remove programs in the control panel and use the Ati software removal utility.

Then, turn off the computer. Before you restart the PC, take the X800 out.

Put the 8800 in and reboot. Install the newest Nvidia drivers and reboot.

Should be good to go after that. Always worked for me.  

what cleeve said

If you want be 200% sure there are no ATI files left then follow what cleeve said, but when u restart with the 8800 in its slot, bash your F8 button and go into safe mode. Once here run driver cleaner pro -> select ATI -> click clean (you'll need to download driver cleaner pro first   ). Once the cleaning is over, restart as normal then install the new nvidia drivers.

I think what cleeve said is probably faster, and more effective

I have always done what blade said with great results. I have seen many issues with new video cards from remnants of old drivers. I would use DCPro just to be sure

Can i properly insert my foot into your proper behind?  

Turncoat  

Just get driver cleaner pro and get rid of your ATI drivers AFTER you have used the ATI driver removal software. DO NOT USE DRIVER CLEANER PRO FIRST. unless you like formatting. then feel free to just format (then hang yourself for buying nvidia   ) I know it is a WAY better deal than the 2900.

I don't think you need to go into safe mode for DC pro but better safe than sorry.

and remember, the universal solution in computing is: if it is broken, format it.

Time to go format my bicycle...