|There's a lot of good software for locking down computers. The first one that comes to my mind is Deep Freeze. There are plenty more so don't be shy about using google to find something that does what you need and is affordable.|
If you have no need for these computers to be on the same network as the rest of the center, or like me in a similar situation, would prefer they weren't, the addition of a second SOHO router would allow you to segregate the two computers away onto a completely separate subnet.
For more information on adding a secnod router simply click on my name above in this response and read my “how-to” guide titled, “Add a second Router to your LAN”.
You'll want to pay attention to "Version 2" in my guide.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.