http://support.microsoft.com/support/kb/articles/Q241/4/22.ASP

WMP:
	/embedding 
	/open
	/close
	/play
	/fullscreen
	/new


/embedding: ?
/open: just open the file, don't automatically start playing
/play: start playing the file as soon as possible
/close: close the file after playback (*only works when used with /play!*)
/fullscreen: start file in fullscreen mode
/new: use a new instance of the player

** Note that "/fullscreen" and "/new" are not supported in V7.