Are you using a "Easycap" or similar named product?
If you are, I had the same problem, what I did was to forget about connecting the audio via Easycap and used a phono to 3.5mm cable (from ebay) to connect to the mic input on the pc.
Make sure "Mic" is enabled to do this on the pc!
I am now having a sound playback problem, very garbled. Whicj I have not sorted yet...................