Needs advice on second display no sound. PLZ.

Hello guys. Someone please help.

I have a second video card in my Dell PC connected to a new sony TV. The video card has a DVI out and connects to the TV via an HDMI input (i am using a DVI-HDMI adapter). The video can be seen on the TV. In the HDMI section of the back of the TV there are L and R RCA audio inputs whose purpose is to feed sound into the TV when using a DVI-HDMI adapter. I have connnected the computer audio via a Y cable on the PC into these L and R audio inputs, but there is no sound. I know the Y cable is working fine because when I connect it into the L and R RCA audio inputs of the component section of the same TV the sound is played through the TV.

The second video card is an INVIDIA and, according to my A/V guy, there should be no problem with the sound, since the sound is managed by the computer not the video card. He says that since the Y connector transmits sound (i.e. when connected the component audio section on the back of the TV) the problem is NOT the PC or the Y cable. He insists the problem is the TV. I have contacted Sony warranty who has sent out a repairman who could not get the audio to work via the L and R audio in the HDMI section on the back of the TV. they even replaced the entire rear connector board of the TV, and still no sound. Sony says the problem is not the TV, but that the video card is incompatible with the TV.

At this point, I think the problem is that either the Sony design is defective or that my A/V guy is full of it.

WTF????