I have my computer hooked up to our HDTV and right now I can see everything on the screen of my HDTV, but I can't hear any sound from the tv, it only comes out of the computer speakers and not on the tv, how can I fix this?
As well, how can I set this up to use a split screen, like making 2 screens and being able to drag something to the tv, like using 2 screens at once. The cord that I'm using isn't an S-Video cord, its another cord, and on the back of the TV it says RGB where I hook it into.
Thanks for any help!

You'd need to connect an audio lead from the audio output at the back of the computer to the audio input at the back of the TV that takes an audio input from the PC. Refer to the instruction manuals for both items to see where the sockets are.

If your TV set does 'picture-in-picture', you should be able to view a small TV picture while the computer input is selected. I don't think you can split the screen but that might depend on the make of TV.