[mcw]

Friend's Touch Pro experienced the same issue a couple days ago. Took a look at it, tried a few things, nothing worked, and I hate having to uncheck the ActiveSync advanced functionality option on the phone.

Then, took a wild stab:
1 - Attach USB cable from phone to PC.
2 - Fire up Internet Connection sharing on phone, and click connect...
3 - Hit disconnect

This action was able to restore the ActiveSync functionality (without having to uncheck that "advanced functionality" option). As soon as I disconnected the internet connection sharing (even if the internet connection sharing doesn't fully complete the connection on the PC), ActiveSync fired up and detected the phone.