I wanted to set up a linux computer that could have multi. user accounts and each person can access that account when ever. I wanted one host computer that someone can access by going to http://12.345.678.90:5800 or what ever port. But 10 users have to be able to access this at the same time (I dont care about lag right now) and they each have to have their own desktop and it wouldn't interfear with each other if more than 1 person was logged onto that computer. Is there a step by step guide for this and hardware specs?

I also wanted to disable the shutdown and other things on that comptuer that would keep people from going far into the network or messing around with the harddrive. Is there any program to do this?