Plz help, lost internet connection after NIC reloc

Greetings:

To free up the 1st PCI slot on my Dell Dimension XPS-T500 for a Promise Ultra66 IDE PCI card (for this card to work, it needs to be installed on the 1st PCI slot), I have to relocate my 3Com Etherlink XL 10/100 PCI to a different PCI slot (the 5th and last PCI on the motherboard). Since then I lost the internet connection in all OS (Tripple boot Win98SE, WIN2K Prof. sp3, XP Prof. sp1). I am still able to access the company NT 2003 server; however, I am no longer able to connect to the WWW. I double check the IP address, LAN settings, TCP/IP Dialup, TCP/IP 3Com, IPX/SPX etc with another working computer and everything seems to be normal. Can anyone please give me a hint of how to fix this?

Thanks in advance for your time and help.