As far as blocking installation, just set up a new user and make their account limited. You be the admin account.
If you are trying to be discrete, try something else. look on download.com for some stuff or search around. Im sure there something out there. I guess im not really understanding what you are trying to do? Maybe more details about what exactly you are trying to do would help.
you could install it and then specify the port it uses, then block that port from accessing the internet. if you dont have a router that blocks ports you could also try firewall software. I have Sygate Personal Firewall and you can block process' from connecting to the internet by specifying the process instead of the port.