We has WSUS running on Windows Server 2003. That crashed. I installed WSUS 3.0 SP2 on a new server running 2008 Server R2. The new installation seems to be working fine - updates downloaded etc - however it sees no computers. I have change the Group Policy to point to the new server.
I believe the problem is the registry settings on the PC are still pointing to the old server. The old server still exists just the WSUS is not running. I have ran the commands to try to force the detection however no change - still looking at the old server.