I’m sure this isn’t new to everyone, but someone internally passed on these instructions for viewing all of the devices installed on your machine. Normally only connected devices show up in device manager, but this little trick will show every thing, allowing you to uninstall devices not currently connected:

1. add DEVMGR_SHOW_NONPRESENT_DEVICES=1 to your environment variables
2. run devmgmt.msc
3. View->Show Hidden Devices
4. View->Devices by Connection
5. Drill down the tree to find the USB controllers 
6. Uninstall all the USB devices under these that you don't want any more

To re-enumerate the present devices:

1. Select your machine at the top of the tree
2. Action->Scan for Hardware Changes

This trick can be useful if ActiveSync no longer wants to recongnize your device correctly.