Firstly check the volume is not low or muted on both windows and the speakers. In windows click the speaker icon in the bottom right of your screen, check the volume is turned up. Then click mixer or advanced and check that all volumes are turned up.
If using a laptop, check that the hotkey control for volume is on. You will see an audio icon on one of your ‘F’ keys, hold the Fn button located near the ctrl and press the volume function key.
Next open Device Manager from Control Panel and check there are no yellow exclamation marks on any drivers. If there are then you need a new driver.
If you are still having issues the sound card may be faulty, this is usually integrated into the motherboard. In a desktop PC you could buy a new PCI soundcard if you have a spare PCI slot in your machine.
You need to goto the manufacturers website, find their support section and there should be a list of drivers for your specific machine. Installing these should resolve your problem. I have a list of links to most manufacturers drivers on my website.
Hope this helps,
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