Inspirion 8100, upgraded to windows xp from windows me, and its a 3Com 10/100 & V.90 LAN Mini-PCI

How about notebook, Windows version, NIC, etc.?

did your laptop come with that card?? if it did, check dell's download section. .. you should be able to find updated drivers for it there..

if you installed the card yourself, check on the manufacture's site for drivers..

That is the mini-pci card I use in my 4000 - W2k id'd it and loaded drivers, Windows Update site had the latest.  The Dell Downloads tab above would have Dell's latest.  What I would do is look in the Device Manager and see if there are two entries with yellow ! marks and load the drivers that way.  You may also have to reseat the card, but if it was identified before you changed Windows versions but not after I doubt it is a reseat problem.  Did you do a completely clean install or upgrade over an old Windows version.  Many problems gooing over old; if so consider doing the clean start install.