Small network, two 2008 R2 Servers with Active Directory. Several Win 7 Enterprise, one XP Pro SP 3. All updated as required.
Two days ago, connectivity between the XP and a Win 7 computer suddenly ceased. Other Win 7 computers can see all others, and show them under Network in Explorer.
All of the computers can be found, using Search Active Directory, from all Win 7 and 2008 R2 computers. However, both Domain Controllers and one Win 7 fail to show the same two particular computers (one Win 7, the main machine, and the XP).
The XP machine will not show the network under Microsoft Windows Network (access is denied).
However, I can access all machines from the Win 7 computer that is invisible! And, in fact, from another Win 7 computer that has not been rebooted lately.
This was a problem in the past, that I could not cure, which disappeared. It is now back with a vengeance.