Dell once gave me the help I needed for the Optiplex 760 with Server 2003 by going to Chat, and it was a breeze... I just needed my Service Tag and had to register the computer in my name.
First, you might want to inspect your system at Dell using your service tag. Look for purchase details, and whom you find listed as owner. If not you, you need to register the computer as for You then wait as much as two weeks to assure the ownership change is in their system.
But I found their Chat support very helpful. Many of the XP drivers were the same. Start with the Chipset.
I will post the links as soon as I have my minimum of 5 posts.