Can't Active Sync - Need Help!!!

[DLCPhoto]

I have had no problems using Active Sync with my VZW TP2, Windows Vista Home Premium 64-bit, Windows Mobile Device Center 6.1.6965.

Just tried this morning, and receive the following:

"Synchronization cannot be started because you are not able to log on to the network and access information. Restart your computer and synchronize again. If the problem persists, contact your network administrator."

I upgraded NIS 2009 to NIS 2010 yesterday, so thought this might be the problem. I temporarily disabled both the Firewall and the AntiVirus, but no difference.

Internet searching showed a possible problem with Outlook 2007 - did a diagnostics through its help menu, 1 problem was allegedly fixed, rebooted, no joy.

I removed the Partnership, WMDC tried to start when I next connected the TP2, but nothing ever happened.

I also upgraded IE7 to IE8, but am doubtful this is related.

I also had to do a hard reset on my TP2 to try and fix a screen alignment problem it had developed, used SPB to restore everything, so doubt that is related, but thought I'd mention it.

I am at a loss. I have a drive image of my OS partition from a few days ago, but I'd prefer not to have to use that if possible, and instead identify where the problem is and 'surgically' correct only that.

Any ideas greatfully appreciated.