How to connect a hitachi CP-x400 lcd projector, logitech x-530 sound system, and a dell inspiron E1505?

In addition, i have a USB sound card (creative USB sound blaster) that i have been using with my laptop and the sound system logitech x-530. I just purchased the hitachi projector and now i want to connect all the devices together so that i can project both my cable box, and laptop and use only one source of sound output (the sound system logitech)???