need driver for USB controller for GX260 - no cd

A friend of mine has me working on two of his GX260's  He had me wipe them clean and then install windows 2000pro.  He lost the Optiplex Resource disks!  I was able to download the drivers for the integrated Video, Network, Audio, as well as the newest chipset and bios off the dell website..  I can not seem to find the drivers for the USB controller on line anywhere.  Does anyone know what driver I need? and where I can get it.   Is it the same driver used for the GX270? (where can I get that) OR where I can get a copy of the optiplex CD (assuming the driver I need is one there).  I can't seem to find what I need.

Thanks in advance.

JZ