Hi thickage,
Right click your GroupWise Icon,
You'll notice the Target will say something like this:
C:\Novell\GroupWise\GrpWise.exe
add the following to the end of that line
C:\Novell\GroupWise\GrpWise.exe /@u-?
-- will ask for username & password everytime.
If you only want to remove the GW Client from startup, navigation to your Start --> Programs --> Startup and remove it from there.
(will only remove it from start up. If click Icon without the /@u-?, GW will still load w/no password required)
Good luck.