[nns]

On my TV, I have to press the "Source" button on the remote to change the source so that instead of getting a signal from the coax cable (like for watching regular TV), it switches to PC mode and grabs a signal from the computer.

It would help if you told us the model of your TV.

Also, on the computer end, what type of port are you plugged into? If it's DVI, then the cable between the PC and the LCD won't carry the audio signal. In other words, there won't be any sound when you're playing things off from the computer to the TV. In this case, you'll need to plug in a separate audio cable from the PC to the LCD. I had to do this. You can buy a regular PC Audio cable from The Source.