IF the live window is active, then the D key should remove the live display and show the desktop. This worked for me sometimes in Windows (always on my Mac), but not consistently.
I solved my problem by
checking Windows display properties to designate my desktop screen as the main screen. For some reason, the remote is display 1 and the desktop is display 2. (OpenLP labels the 1 and 2)editing the windows registry to turn off the splash screen (if you don't want to or don't know how to do this, then I suggest removing and reinstalling OpenLPRestarting OpenLP and in settings, made sure that the remote screen is the one with "Use this display..." checked
In hindsight, I probably could have used the remote to show the desktop... Haven't checked that this works, though. We had a problem before getting the remote going.