NIC will not take DHCP address

Running win2k with 3COM NIC and it will not take a DHCP address from my Linksys router. However I can assign a static IP address and it works fine. I was able to ping the NIC as well as take remote control of the PC using VNC. I have changed out the NIC and had different problems, like the NIC did not appear in the device manager. It is possible that the PCI slot is bad??? I am not sure, I tried different slots same problem.