What i'm trying to understand is what cable can I use from the audio out of the PC to connect with the old audio in on the tv, you know the white and red end cables?
"white and red end" - are those RCA connectors, that look like the ones in this picture?
The V is composite video, L & R are left and right audio. You can get a cable with RCA plugs on one end, and a 3.5mm plug on the other for the PC.
However, audio and video go together, so if you select a particular video input, the audio has to be coming in through the correct sockets for that video input. So, if you select "PC" on the TV, both the video and audio have to go in through the "PC" inputs. In the case of my LCD TV, the PC audio input is a 3.5mm socket, not RCA, so I use a cable with a 3.5mm stereo plug on each end.
Can you tell us the make and model of the graphics card, and the TVs? Your graphics card might be able output VGA from the DVI socket (with an adaptor), so you'd use that, so you don't have the worry about converting DVI to HDMI. Then we might be able to see what audio input sockets correspond to the PC inputs.