Maybe you could buy a USB if the computer at your school supports that format and then flash a portable version of the distro you want to use. then you have to make the computer boot from usb and voila! you now have a school computer not running windows or OSX for the time being until you remove...
So I'm on my 69th install of Linux on my 16tb drive and I have all of my favorite flavors of the kernel. so this is just my introduction thread. also whats in the sprite bottle is windows and mac users tears.