|what exactly does the popup window say? it sounds possible that someone in IT may be initiating these reboots.|
save your stuff and close your apps. go to the run line and type:
shutdown -r -t 30
that will reboot your PC after 30 seconds. Does the popup window you see match the other one the teacher is getting at school?
are the PCs plugged into a surge protector?
what about a battery backup or "line contitioner?" A surge protector will protect against sudden INCREASES in power ("spikes"), but not against "dirty" power or "brown-outs," where SOME power is still flowing but not the minimum required to run the PC. This will cause reboots and damage hardware, but you typically wouldn't get a windows popup in this situation, the system would just crash...
still, it might be worth looking into. i know most school buildings were built sometime prior to 1654 and have yet to receive the funding to catch up on little things like plumbing, electrical wiring, or chem books with periodic tables past element number 99 (there's something like 116 known elements now).