First I'd check the Dell web site as they have specific drivers and updates for their PC's. When you login (you may need to register) to the Dell website it will ask you for your service tag and serial # so it can identify what model you have. I would not attempt downloading ATI drivers from a third party site as the card in your system is OEM for Dell.
Even with the latest drivers on my second PC the NVIDIA video card is still giving me issues and forces me to select Directx 9 instead of Open GL. This was not an issue or me (and others) prior to some of the most recent updates. Hopefully a fix will be rolled out soon to correct all video issues.
