INT B3 - ZIPKEY - REQUEST POP UP
        AH = 7Dh
        BL = index number to simulate pressing a hotkey
            FFh for immediate popup with no playback on return
Return: CF set on error
            AL = FDh already busy with another request
               = FEh illegal function
        CF clear if successful
            AX destroyed
            window popped up and was closed by the user