Problem with iPAQ and Activesync (WMDC)

Hi all, my problem is as follows: I have recently upgraded my XP Pro to
Windows Vista Business Pro and the method used has been an upgrade instead of
a clean installation because I needed to preserve all my settings and files.
One of the problems encountered after the upgrade is that I am not able to
sync my PDA with the PC. After trying to find Activesync everywhere inside
the OS I finally relaised out that it was not present. I searched for it and
discovered that now it is called WMDC.
Well, I init WMDC and it asks for the type of conection used, I choose USB
and Bluetooth then the dialog box disappears and nothing else appears. WMDC
is not started in my OS.
I would apreciate any help from you, and thanks in advance.
Regards from Spain.