Have you tried to run the PC through the DVI port on the tv, if there is no DVI output on the PC, look for a VGA port, if there is, buy an adapter (VGA to DVI), if there is not,I have no idea. Good Luck!
Is the volume of the bar itself on, it can be an issue of the product, else you could enjoy a long, mind-numbing talk to support or send it back saying it is faulty.