Prevent More Than One Logon At A Time 1

[Talc]

I run a school network with 250+ stations and 1100+ users, the stations run Win98 and the servers Win2K.
My problem - I wish to prevent users logging on more that once at the same time i.e prevent students borrowing logons or prevent users logging on to another machine if they have 'forgotten' to log off elsewhere.
I believe there is a program 'NTName' that can be used in scripts. Has anyone experience of this or any other surgestions I can use?

Thanks for looking

 

[PAndersen]

http://www.jsiinc.com/suba/tip0200/rh0296.htm