Make sure your window$ machine is set for DHCP, then maybe refresh the DHCP so it gets the DNS address properly. If your Windose machine is on a hub or switch, then it won't always get the new details until the next DHCP refresh, which might be 24 hours away, particularly if you have changed your server name (eg from a restore) as the hardware and mac address will still be the same. You may also need to ipconfig /flushdns to clear out any stale cached addreses on the windose box.