group policy

I’m using Windows 2003 server on a small windows 2000 network. I need to lock down one user account because it is a public computer and we need a default user logon that is restricted. I had the group policy and mandatory profile working on all the stations until the servers hard drive failed. So I changed the hard drive and reinstalled. Now I can no longer get the group policy to effect any of the work stations. I took a workstation off the domain, and then rejoined it, still nothing. The profile works, but it is still using the old policy. Is there a way to make the workstations use the new policy without network wide reinstall? How do I get rid of the old one?