I'm setting up my Q4 machine

. I would like to have an admin account that I use to install/remove progs, and a user account that is only for playing. I want the layout/shortcuts/desktop and everything to be non-adjustable. I just want to login and fly with it. I'm putting it here rather than the software forum because it's kind of off-topic as far as arcade machines go. At least until someone comes out with a clean cp idea.
Where is a good site that shows how to set permissions? All I get is
junk sites.
Is there a way to allow downloads for Q4 stuff of the Q4 servers?
I'm under the assumption I can set services per user so I can cut out the crap i don't need to play games. <-- I can search here for that.