INT 33,0 - Mouse Reset/Get Mouse Installed Flag

	AX = 00


	on return:
	AX = 0000  mouse driver not installed
	     FFFF  mouse driver installed
	BX = number of buttons


	- resets mouse to default driver values:

	  .  mouse is positioned to screen center
	  .  mouse cursor is reset and hidden
	  .  no interrupts are enabled (mask = 0)
	  .  double speed threshold set to 64 mickeys per second
	  .  horizontal mickey to pixel ratio (8 to 8)
	  .  vertical mickey to pixel ratio (16 to 8)
	  .  max width and height are set to maximum for video mode