WMDC refuses to sync

HELP! My WMDC just stopped syncing all of a sudden. It worked fine from Nov
07 up until about Feb 08. Now all I get is this red cross on the WMDC with
"error." Error message on my PDA Activesynch says, "Port not available:
cannot communicate with the PC because the port is not available. Another
program may be using the port, or it may not be valid. Close any programs
that use the port, restart the device and try again."

Tried all sorts of stuff from all sorts of forum (including this one). I
uninstalled WMDC, and reinstalled it and now it just freezes at the WMDC
start up screen that says, "Please wait while WMDC starts". I have to use
task manager to end the task.

I've tried all sorts of things, even reset my laptop to factory settings
(lost all data), reset my PDA..... downloaded drivers, deleted and
re-established partnerships, switched off firewall...... etc....etc...
nothing worked. It's very frustrating!

Anyone has any ideas? Please help!!!

Cheers,
Trish

p/s: my laptop is running on Vista and PDA is Win Mobile 6