Does anyone know if i can access one central computer from three monitors in differant rooms without more pc's?
Yes. You're looking at a mainframe setup. Now, I'm not sure what hardware you'd need to connect the monitor, keyboard (and maybe mouse) to, as you'd need something to make each station a terminal...but it could be done.
You would have to buy a graphics card capable of producing video output to two or more monitors. Matrox make a lot of dual monitor cards. I've even seen one of their cards support 4 monitors. You would have to buy monitor extension cables if you wanted to place them in different rooms. Your other option is to buy a load of small computers (called thin clients) and have them log into your main computer. Check out Microsoft's Terminal Sever software
It would work, though it's not cheap, and not a picnic to setup for the uninitiated. I don't know exactly what your needs are or how much effort you are willing to put forth. But if you have the knowhow and you don't specifically need Windows, you can do this for only the cost of hardware using the free operating system Linux. All Linux/Unix systems have the capability of acting as a terminal server.
as far as i am aware you just need some old pc's with a network in each and a boot ROM on the network cards
If you're talking about Microsoft Terminal Services and not an actual Microsoft Terminal Server, you're right. But this technology is very limited, works only on XP Pro, and allows only one user concurrently. See this article.
So I believe that you are not ready to spend extra money to buy more PC's. To make a Terminal setup first you have to buy some Thin clients like [link=http://h10010.www1.hp.com/wwpc/us/en/sm/WF04a/12454-321959-89307-338927-89307.html] HP Thin Clients [/link] (You can get more cheaper from other companies). If you want to go for the cheapest way then go as Anti Trend suggests, install Linux. You will have a strong system with better security. Every thin client have USB ports PS/2 ports and a RJ45(which is network card). You dont need to buy monitor extension wires. Just a network wire will do all your work.
