Since the device was synchronizing earlier and you also mention that you
have installed the originally supplied version of ActiveSync it wouldn't be
a driver issue the way I see it. Here are a few recommendation if its
not getting detected under the Device Manager:
1. Click Start, then click Run. Type the following:
Click Ok. This should open up the device manager.
2. Connect your Pocket PC via USB and see if you are getting an entry at the
bottom Windows CE USB Devices.
3. If not, then on the menu click Action -> Scan for hardware changes.
If that doesn't help, try a different USB port. If this also doesn't help,
then try connecting to another computer and see if its failing there. If it
does, then the issue might be hardware/cable related.
Microsoft MVP - Mobile Devices