Hi,
Shane, I think the problem is only in the driver update. Normally those previous versions drivers were supplied as cds and there would be some update which one would forget to update. Then these drivers became obselete, as is the system os, and therefore most companies would not give supporting drivers for the same product. Windows 7 auto detects the drivers from the connections and also from window updates.
The solution would be be look in to the other drives, where there is usually a back of all the software supplied with the laptop. I would advise you look out for a similar laptop in xp configurations and then copy the drivers from their folder to your computer and activate it by installing the exe files from those folders. Normally i find some numerical exes as drivers stored in other drives in xp system of the laptop.
It seems that the thread owner first installed the windows 7 and then xp without supported software cds of the xp.
Update: Please see this link also
http://support.microsoft.com/kb/870702 If it is mother board drivers, it is best to go to their site or alternate sites and download the ethernet drivers