This aint gonna be easy.
Well, one way is. You should have a "function" or "FN" key on your keyboard, probably between the alt and ctrl key. You'll see that it may be a different color or have different color text on it. Some of your "function keys" (f1, f2) and perhaps other keys may show other symbols in that same color. One of them, usually F5, should show what looks like a pair of screens...one dark and one white. Holding down the FN key and then pressing F5 repeatedly should walk you through laptop monitor on/external off, laptop and external on, external only on, then back to laptop only.
There is probably also something in your computers display properties (right click on the desktop, choose properties, click 'settings' tab and then advanced) that allows you to setup a 'theater' mode, or its something in the ati tuners software that lets you set up the theater mode or tv output mode. Many current laptop graphics chips can do a basic 'dual screen output' where the tv stuff goes out the video out port on the back of your laptop while the main laptop screen still shows your windows desktop.
I dont know what sony uses for a display chip, or anything about ATI's tv tuner s/w, but you're looking for something that says 'theater mode' or 'dual screen' or 'dual output' modes. Note that the tuner, the projector/monitor and everything else should be plugged in and turned on before looking as sometimes the software will only let you manipulate the settings while it sees the actual hardware hooked up and powered on.
Its a little rocket science...once you find it and enable the tv output to the 'external monitor' or 'second screen', it should work great.
