I don't think it should be a problem for students, all they need to do is install virtualbox (double-click installer on windows) and import the VM image (running a GUI wizard). I've done this before at a company I worked, new office building had Macs and OSX but needed to use some proprietary Windows app for parts of work so I deployed VBox and along with a preconfigured WinXP image to every machine. Nice part of virtualization is the hardware is virtualized so the image should work exactly the same across all computers, no hassle with hardware support unlike using bootable images.

Just find some lightweight distro that's easy to configure and is supported by virtualbox guest drivers.