Name Resolving problem with Micrsoft Exchange Server

[Quino]

I am having a problem with a computer that cannot acess the Exchange server anymore. The computer's Power supply died and it took the Motherboard and CPU so I had to change the CPU and Mobo. The computer had win2k so I just let the win2k pick up the new changes and instaled the drivers that were needed. The computer can access everythin on the network and even log to the NT server. However, when I fire the outlook 2000 it tells me that the outlook address book can not log on to the exchange server. I wnent ahead and deleted the profile and recreated iot and when I try to check the name for the inbox I get the error "The name could not be resolved. The microsoft Address Book was unable to log onto the Microsoft Exchange Server Computer. I do not know what to do and I have tried searching on the net but I have not been able to find and answer. Any help will be appreciated.