Teachers are always stumped when they see this dilemma, and usually suggest restarting, thinking the computer just freaking out.
Uneducated users also don't know "Ctrl + W" and "Alt + F4" can be held to very quickly get rid of this problem. However, these shortcuts will not solve the problem if it is held long enough to crash.
Student 1: *Walks up to board*
Student 2: (Whilst student 1 is at board) *Presses and holds "Windows + F" for an extended period of time, then turns off monitor*
Student 1: *Walks back and turns on monitor, seeing the hundreds of search windows* "Son of a biiiitch, I got Windows F'ed in the A"