Try this:
1. Detach all headsets and external audio devices.
2. Look at the task bar on the bottom of the screen. On the far right there should be a sound symbol, it's the volume control. If it isn't there try clicking the little arrow pointing up.
3. Turn the volume all the way up.
4. Right click it and select playback devices.
5. Find the one called speakers and select it. Then press the button that says set to default.
If this fixed the problem, glad to help.
If it didn't, try clicking configure, then click the test button. If you don't hear any sounds then it may need drivers or could be a bad wire connection.
To find the drivers, just google your PCs model number and sound driver *example- emachine h30 sound driver" and...