Go to Control Panel - System - Hardware tab - Device Manager button. Expand the Sound listing, and see if there are any exclamation or question marks showing. If so, then it looks like you need a driver for your sound card.
You need to install your driver for the sound, it usually comes on your motherboard CD,. If you do not have a CD anymore, open your PC and check the name on your main board, then, Google search that name together with “download driver sound” Check out main sites, not dodgy pale looking websites, but the manufacturer, of your motherboards, website. Download this, install it and DaDaaaa Cheers Atlantic Computers