Hello,
You should be able to on the Pocket PC, choose Start-->Settings, System Tab, Remove Programs. The, from remove programs, in the list of programs, choose Groundspeak Wherigo Player. This should remove the application. Make sure you don't have the Wherigo Player running. To check that it's fully removed, go to Start-->Programs, File Explorer and navigate to My Device, Program Files. There, you'll see a Groundspeak folder that contains Wherigo/Player. After removing the program, if you still see this, you can delete this folder.
To recap:
The Player installs to: Programs/Groundspeak/Wherigo/Player
The cartridges are in: My Documents/Groundspeak/Wherigo/Cartridges
David.
Thanks - that seems to have worked.