Happens all the time. Normally means someone has reinstalled windows and has forgotten to activate. It's not that it isn't genuine, but the grace period for activation has expired.
We have enterprise on our school computers and this happens every once in a while.
I think you're exaggerating just a bit lolROFL what an irony...
I say that because schools in HERE are still using Windows 98 and ME mostly lmao!!!
God knows when we will migrate to XP which exists since 2001. xD
I will probably be dead by the time we move to Windows 7 in our schools xD!!!