Windows 7 - Connecting my Computer to LG TV no SOUND through HDMI

Help me , im trying to find a way to have sound coming out from my LG tv. I have connected my computer to my LG tv via DVI cable. THE HDMI port of the cable connects to the tv , the other part connects to my pc( my pc has no HDMI port) . The picture is perfect HD but there is no sound
- i have done research and i have tried the playback option tab to set it to default and i have clicked the show dis-activated devices...
- what i did was i connected my laptop to my LG tv via HDMI cable(both ports) and the sound worked perfect on the TV!! . i have a sony vaio laptop with intel high definition audo device.
- my pc has realtek high definition audio

NOW CAN ANYBODY SUGGEST ME ANYTHING ??? MAYBE DOWNLOAD ANY DRIVERS ???

G'day sam. Right click the speaker icon in the system tray & see if it is similar to the screenshot. If you set the hdmi as default it should work.

I know in times past it has been a real hassle to get mine to co-operate.

this is what i see on the playback

If it looks like the first screenshot on your laptop the problem could be with how the hdmi cable is connected to the desktop.

Maybe you need a special kind of adapter to allow the sound through.

on my laptop it looks exactly like your screen shot and the cable is not even connected . now i think it is my PC's problem , mayby a driver or idk. And my PC is hand build , we bought all the parts and connected them. so now that on my laptop it shows the HDMI device intell(r) high definition audio hdmi not plugged in , and on my pc it does not even show it makes me think again its my pcs prob not the cable ????

A DVI connection from your video card won't output sound to the TV.
You need a video card that has an HDMI out connector.

i think so too :/ , how much will they cost

Newegg.com - Computer Hardware, Video Cards & Video Devices, Desktop Graphics / Video Cards, Radeon HD 6000 series

ahh to much money , anyway thanks a lot