I have trouble with xp sp2 recognizing HP stuff, so it is probably a driver issue. Have you checked the device manager to see if there is a yellow exclamation mark next to the NIC?
Install chipset drivers. I know for a fact Dells are bastards, check device manager, I wouldn’t be suprised if there are some other unrecognized devices present.
Ethernet Controller, Multimedia Audio Controller, SM Bus Controller and Video Controller are all missing drivers… WTF.
IB they all auto-install after that. Do you have the mainboard utility/driver CD? if not d/l from manuf. website. Its gravy, no need to sweat. 
umm… i’m not really making fun of you… so don’t get all emo.
an ide cable has two connection… usually first is primary and second secondary… furthermore, the jumper settings on the cd drives themselves will dictate the primary from the secondary…
Well, brought it into work, downloaded some Intel 10/100 LOM or whatever driver, and my internet works now… installing SP2 as I type.