Prevent users from logging oto a domain compter

[Viscereal]

I have a wierd need.

I only want to allow ONE user account to log into all of my domain (Lab) computers. I am running citrix and want to allow only the "lab" user to log onto the computers.

Once this account is logged on, the users will click on the Citrix Logon Icon and authenticate into the citrix farm and go from there.

Any thoughts on preventing those same users from logging onto the "lab" computers with their domain account??

Thanks for any help all!!!!

Vis