[Dave M.]

Bxboy,

Why are you using the headphone output? Many computers have a line level
signal coming out of the back. This would be a better signal for your
Yamaha.
If these bedroom external speakers have an integral amplifier then the
line level output would be a good choice there, too. If these are unpowered
speakers then the headphone output might work. I doubt it will sound great,
though. Use the Y splitter and then make some speaker cables using RCA phono
plugs, zip cord, and whatever connects to the speakers.
I've no idea why your internal speaker isn't working. Poke around in your
control panel.

Dave M