Motorola MPx220 Smart Phone and Vista Ultimate 64-bit

I have a weird problem. I tried to hook up my MPx220 to Vista and the OS just
wouldn't recognize the device as being connected. No "Found new hardware"
notification popped up when I plugged in the device to a USB 2.0 port. I let
it go the first time. I then had to reformat my hard drive and reinstall the
OS for some reason. Now I get a "Found new hardware" notification when I plug
in the device. Vista even searched online and installed the right driver. The
device shows up in Device Manager as a mobile device or as "Motorola MPx220
smart phone". But now the Windows Mobile Device Center doesn't recognize the
device as being connected even though Windows Device Manager clearly shows
that the device exists.

Has anyone experienced this kind of problem before? What can I do about it?

Thanks.