Network driver problem

Question

A refurbished Dell Optiplex GX260 P4 2.6ghz XP PRO bought from recoupIT bought 8/08....that I had tried to restore with a Windows xp disc.....after my friend's son mess it up with spyware etc.....but I think I
repartitioned the hard drive while reformatting it......and I thilnk something happen to the network card driver....because can't go on internet......It says the network driver is missing for the card that is installed and/or is not configured.
This happened after I used the ''operating system'' reinstallation CD for Window XP Professional Service Pack 2
How can I get it to work again?
JOHN