This was posted a while ago, so it's probably resolved, but just in case:
If your "Netware client service" is not showing up in your Local Area Connection (or whichever network connection you use), it is being hidden by a service with a similar name. To access the list of services on your pc, go to Start > Run, and type
services.msc
This will open up the list of all the services on your pc. Go through the list untill you find the service relating to Netware client, i'm 99% sure it has the same name.
Once you've found it, right click on it and select "stop". Once it's stopped, right click and open it's properties, and change it's status from Automatic to Disabled.
Reboot your PC.
When you access your Local Area Connection properties now, you should be able to see the "Netware Client Service". Click on this and then click 'Uninstall'.
Reboot PC.
You should now be able to get into the user account control from Control Panel, and change the way users log on/off.
