Prevent write in the home directory in a client active directory

Hello,

I have a win 2003 server domain controller and win 7 clients; i want that the domain users, when they do logon in the clients, can't write in the local disk of the client

I configured a group policy in the domain controller that prevents to the domain users to write in the local disk but not in their home directory; can i configure a group policy to prevent this? Which  parameters have i to set in the group policy? Or is there another way to prevent the writing in the home directories?

thanks