INT 33 - Mouse Systems MOUSE DRIVER - POPUP.COM - INSTALLATION CHECK            
	AX = 0070h
	BX = ABCDh
Return: AX = ABCDh if installed
	    BX:CX -> data structure (see #03188)
Notes:	this function is also supported by the Genius Mouse 9.06 driver
	the v7.01 POPUP.COM and menu drivers also check for the signature
	  CDh ABh BAh DCh at offset -2Ch from the interrupt handler
	if POPUP is not loaded, the returned data structure contains the proper
	  signature at offset 00h, but not at offset 08h


Format of Mouse Systems POPUP.COM data structure:
Offset	Size	Description	(Table 03188)
 00h	WORD	signature ABCDh
 02h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	pointer to info structure??? (see #03189)
 06h  2 BYTEs	???
 08h	WORD	signature ABCDh


Format of Mouse Systems POPUP.COM info structure:
Offset	Size	Description	(Table 03189)
 00h	WORD	driver version
 02h  8 BYTEs	???
 0Ah	WORD	segment of ???
	???