Confirmed Fix
Here's a confirmed fix:
Launch Parallels, and start Windows.
Click Start menu, select Run...
Enter the following in the Run dialog box (this will stop the Coherence service and remove it from the service list...it doesn't actually delete the program, so fear not):
Reboot Windows
Click the Start menu, select Run...
Enter the following in the Run dialog box (with quotes):
Code:
"c:\program files\parallels\parallels tools\cohrence.exe" install
Seems Parallels has a typo in their executable name (note the misspelled cohrence.exe file)