We connected our Compac PC to our Vizio TV and now we have no sound. We have Windows VISTA for our OSHow was it hooked up?
If you used HDMI you will have to select your output on the sound card to go to the detected DIGITAL device.

if you used some other method let me know and I'll try and ts it for you.Honestly I am not sure we plugged in whatever was used to connect the monitor. Unfortunately I am at work and won't be home until 5 cst. I am assuming its not connected with HDMI, but could be wrong. Will check tonight when I get home.If it is the often used VGA CONNECTION cable then you will need a separate sound cable for input of audio,truenorthThe sound works intermittently and us connected by typical cord believe it says rgb. When computer is logged off no sound comes from tv either. Please don't make it so hard to help you.Is this your cable?
http://www.ehow.com/about_5098860_rgb-cable.html
If you don't know what kind of cable you have used do some research (Google for instance) so when a question is asked you can give an accurate response. Or take a picture and post it in this thread.truenorthtruenorth, dont make me sound like an idiot. I was working on this at midnight while my husband was asleep, took it upon myself to figure it out on my own. Yes that is the cable and I realize it probably isnt the right way to do it, just wanted  it up and running for the kids. We both work full time and have 4 kids and life to tend to so, while I want this to work, it isnt high on my to do list. We have an HDMI cable, but our pc is older and doesnt have an HDMI port, I dont want to spend 40 or more dollars for a usb/hdmi convertor if I dont have to. Can i do it without, or will it be best to just hook up speakers to the computer and be done with it.Actually any effort (implied) to make you look like an idiot was NOT my intention.My intention was and remains to try and help you with your issue as completely and expeditiously as possible. Often it becomes necessary to  get more (and hopefully accurate ) information from the poster.That was the case here.I SUGGEST to you that a VGA (for the video) which should be common to both the computer and the tv and then probably a stereo mini plug (computer end) and unless the tv has a mini stereo input female jack at the other end for the tv a red/white rca plug for the audio. If you can elaborate on all the output (computer) and input (tv) jack options you have AVAILABLE perhaps other options will become available.The way i have suggested is a very inexpensive way of achieving your goal.Please remember you can see your equipment we cannot.So the more you can tell us the better.truenoth