Possible Duplicate:
Minimize all windows on the active monitor
It's quite widely known that Win+D will minimize all windows (i.e. show the desktop), but there doesn't seem to be an equivalent for one monitor only.
Very often I will press Win+D to open up some application from the desktop only to find the video player I have on my secondary monitor has been minimized as well. Due to bugs in the player, when I restore its window, the movie will either restart or the player and/or the display driver will crash.
Interestingly, in Windows 8, even though there are separate task bars (and start screens!!) for each monitor, the show desktop feature still works globally.
Solutions for either Windows 7 or 8 are acceptable.