Logging on XP machine

when I log on to XP machine, the autentication process is exterimily slow. When I unplug the network cable from the on board NIC card, it logs me on fast. It seems the problem is form the NIC card, I alrady loaded the updated drivers for all the components.Account for the computer and user is created on the server (2003)and it is active. Please lem me know if you have any idea….Thank you.