Need to reinstall Ethernet Controlling Driver???

Hi,

 I just redid my Dell XPS back to new....it has the Windows XP, Service Pack2....but it now I can't get on the internet, I use DSL. I called my provider and he had me go to Control Panel-System-Hardware tab-Device Manager-....and down on Other Devices, there is DVC90, Ethernetnet Controller, RAID Controller...these all have question marks beside them. He said I need to reinstall my Ethernet driver, but I cannot find it on any of the disc that came with the computer. Is there some place simple to go to and download this. When I looked for there seem to be a bunch and I didn't know which one to download and I did try a couple but none worked...one wouldn't even work of the disc. I am having to work off my laptop and load on a disc then to the computer. So any help would be great!!

Rhonda