Network Access on Windows XP - Administrative Tools

[Termoyl]

I apologize if there is already a thread on this, I checked and was unable to find one. I am having trouble restricting network access to only users in a Windows XP environment. I have 2 machines, each with 2 user accounts on each. 1 of the accounts on each machine is set to administrator, which I use my name for, and the others, are set as users only, which I denied network access. However, even when I permit administrators and power users only for network access, and remove the students, it denies access to EVERYONE. I restrict and permit access by going to Control Panel -> Administrative Tools -> Local Security Settings -> Local Policies -> User Right Assignments. I restricted network access to the Student user in which was catergorized in "Users" However, it denied everyone access. Does anyone have any suggestions? Thanks a bunch.