Upgrading from Windows 2000 & Network Issues

[Guest]

Upgrading from win 2K to Win XP Prof. completes succesfully BUT the Network
Neighborhood, File & Print Sharing do not function any more.

If I do a clean install on the same computer everything works just fine.

Any ideas why the upgrade trashes the networking?

(Have a ghost image of the Win 2K so I can go back and forth with Upgrade or
Clean install).

 

[GTS]

Did you check the status of your NIC in Device Manager? If could be a
driver issue.

 

[Guest]

No issue with NIC; have access to the internet, can & did do all the XP
upgrades.
What is broken is the Network Neighborhhod, File & Print sharing. Following
the upgrade there is no way to install sharing.