Here are my notes from sorting this out in the past:
Requires Windows Mobile Device Center for USB connection
Windows Mobile Device Center requires that the following service is running:
Windows Mobile-2003-based device connectivity
If the service is not running or won't start, try changing the service logon to "Local System Account" in Services
NOTE: Might need to reload Windows Mobile Device Center. Will receive errors, but can then manually start service. Installer is located in URC MX-980 Connections Issues folder