PC to HDTV = No Sound!

I have my PC hooked up to my LED HDTV through from DVI to HDMI.
My video card does NOT support sound through HDMI or because it is through DVI to HDMI. Not sure since I'm not too tech familiar =(

On the back of my HDTV, there is a place that says PC / DVI Audio In
(I purchased a stereo cable, like the ones for the car AUX for Ipods and put my output PC to that PC/DVI Audio In)
That doesn't work.

So I purchased an RCA to Aux cable, where the AUX is from my PC Output to my regular Red/White components to the back of the HDTV.
That still doesn't work!

I did check my Sound settings on both the PC and HDTV.
Is it because I can't use the HDMI TV Input with a sound from PC of some sort? lol

Not sure what to do, if anyone could help me!

Thanks in advance! =)