I fired up my old compaq desk top to use downstairs and it worked fine but no sound. Last time I used it there was sound. SoundBlaster Live card. I checked all the muting/volume, driver, and all is ok there. I reseated the card, borrowed some other cards, checked the speakers and lines-still no sound even with headphones. What might the problem be?
You can go to Control Panel / System / Hardware / Device Manager / Sound , Video and Game controllers
and look for any Yellow or Red devices.
And also Control Panel / Sound and Audio Devices
Look to make sure the Proper Audio Device is selected.
Have a Good Day.
Follow Don's advice, and also, sometimes you need to uninstall and then reinstall the sound card in device manager and then reload the driver. If you are running Windows as, most people except artists and tekkies who run a Mac or Linux, windows has a funny way of crapping everythig up. Now where have I heard that before?