OptiPlex GX260 Network Driver

I apologize if this question has been asked and answered before:  When I try the search function, I get "Error Location Documents" regardless of search term.

I have an OptiPlex GX260 as a backup machine and recently installed XP.  After noting that the built-in network adapter had no driver, I went to the Dell website and used the feature where it searches the computer for needed drivers.  I downloaded and installed all recommended drivers, but the network adapter still has no driver.  Where do I find a driver for the network adapter of this machine?