Restrict Logins Through Group Policy

Hi all.

I want to be able to do the following though Group Policy on my Windows 2000 Server:

– Restrict the users to only logging in on one machine at one time. This is so people don’t leave themsleves logged in around the network.

-Setup Group Policy to log users out after 45 minutes. (I thought I found the location of this in Active Directory Users and Computers. But when I enabled it for users and set the time for 45 minutes, it didn’t do anything.

Thankyou