DNS NOT WORKING

I HAVE NT SERVER 4.0 SP6. DNS IS NOT WORKING.
I AM CONNECTING TO MY ISP VIA MODEM.
I HAVE REMOVED AND REINSTALLED REMOTE ACCESS
AND TCP/IP, RECONFIGURED DIAL-UP ACCOUNT.
I TRIED HARD CODING DNS NUMBERS. I REINSTALLED WINDOWS USING REPAIR METHOD.STILL NOT WORKING. WHAT GIVES?