I have seen in some schools and cyber cafes, multiple monitors, keyboards and mice connected with a single CPU and act independent of each other. I have a good performance PC having Windows 8 Pro OS. I want to make a similar system. What are the extra hardware or software required to do this? Thank you.
Probably just the hardware. For example for monitor, you should be able to plug in an external monitor and configure it (Clone / Extended Desktop etc) with something like Graphics Options (right click on the Desktop), Output to. For keyboard/mouse perhaps even easier, though why one would want that for more than one mouse is not obvious (what do you expect to happen if one moves up and the other down?)
It is not possible.
I have seen internet cafes use 'slim client' where they have very small computers that connect to a server. The server runs 'virtual machines'. The input from the small computers is sent to the virtual machine on the server and the video/audio is sent back to the small computer. Unfortunately this is of no help to you.
I think you will need to buy another machine.
Having said that.. I just read an article about turning a Raspberry Pi into a thin client. So...you could do it. But realistically another machine is more feasible. http://rpitc.blogspot.jp/