We are having several systems that have the same problem. User X will be able to login to their computer and access the Internet, etc. However, when they try to access a Windows 2003 Server they can't get logged in. We have tried numerous things and the only thing that seems to work is to remove their active directory login and recreate it. This then seems to work for a while but for some of them the problem comes back again.
Anyone else logging in on these computers has full access to everything and can access any of the servers that they have rights to.