You need a few things. First a copy of Edubuntu which is a Linux distribution. It is an operating system. Under the Linux system there are applications that are similar to the Windows/Microsoft office environment that are free to download and install.
You can learn more by visiting http://www.edubuntu.org
Next you need an old computer or maybe a pair to make into one functional server. That is the starting point for this video series on YouTube.
Some of the advantages of doing this is that you keep old computers out of landfills, you lock out most of your problem about user mischief and you get to save a bit of cash on replacing desktop units.