I use Windows 7 SP1 x64 Ultimate and the Print Screen key stopped working: no image is put in the keyboard when I hit Print Key. Nothing happen when I hit Alt + Print Key either.
The issue affects the two keyboards that are connected to the computer. Windows' snipping tool works fine. Copy-pasting text works fine too.
I haven't tried to restart the computer, my guess is that it will work then, but I am curious to know what could cause the issue.