NT and 3COM 3C509B

I have a NT Server with SP5. The network card is now am 3C509B-Combo. I have no problems with the hardware instalation, but I cannot see my local network across TCP/IP. The machine can see other computer, but I think that is ?cause I also installed NETBEUI and this computers are not in my net, they are in INTERNET. Have you an idea? Also, I recently made a clean instalation.