No external network after changing NIC

After changing the nic in my W2K Server I lost connection to the internet. I configured it to the identical parameters as the original NIC and it worked for about 8 hours. The next morning I still had my internal network but had lost the internet. The W2K box is running active directory with DHCP and DNS being handled it.

It has been quite q while since I did any W2K work so please ask questions for any info I may have left out.

Thanks in advance