I have two different computers that run windows 8. Sometimes, for no reason the keyboard malfunctions. Instead of typing r, It opens the run window, or when I type m it minimizes a window, and a bunch of other weird stuff. But when I log out and log back in to my user account, it returns to normal. This happens to both computers randomly.
This scenario so happens when pressing the windows keyand pressing those buttons (windows key+r opens run and the windows key+m minimizes) so therefore it must be a faulty windows key on the keyboard.
I suggest getting a new keyboard or removing the windows key by prodding it up and re-seating it again.