32 inch vizio tv getting sound but no picture

Hello,

I have been trying for 2 weeks to hook my Windows 7 laptop up to my vizio T.V via HDMI but I always get great picture but no sound.

I have tried a few suggestions I've seen online like going to the sound properties and setting the speakers to DEFAULT but it still doesn't work.

I would be sincerely grateful if some can help me because this is a bit draining when you don't know what your doing and explain as simple as possible

Thanks