Televiewer+laptop Latitude CP M233XT

Hi All

 I am having a problem viewing both the tele and the laptop at same time when I toggle through with FN+8 I can only have the tele or laptop but I need both (karaoke).My first thought was that there was not enough power brought a power supply no good, then after reading some posts I checked on the driver Neomagic MagicGraph 128XD ok.The only other thing I can think of Is that my video memory may not be enough 2mb ,If anyone can help me on this It would be very grateful .

Many thanks for letting me on the board.

Albondi