Listen to BurbankKarl's address as well. If the NIC is enabled in BIOS then the specific drivers for the motherboard are not being detected by Windows, it will not detect built in stuff correctly (Like modems, correct video card, NICs, correct soundcard, etc...). You would need to load the correct and updated drivers from DELL for the motherboard and onboard chipset.
hey, I have 10 Dells at work here...and I am tech support....among 100 other things. Just posting what works for me!