security: protecting local c: filesystem on WTS server.

I have made a WTS enviroment for a select group of users.
I have tied down al use of windows desktop.
Users can only start the application thats on their desktop.
This application is a access application and produses pdf files.
Users need to manage these pdf’s by copying them to network folders. The network folders on Novell servers.

So I need to give users the explorer back and access to the c:\ folder. I’d rather give only access to “my documents” but thats not possible.

If I give them access to c:\ they can browse to c:\program files and access and start any program they want. How would one protect this on the microsoft way ???

Thanks for tips !!!