I've had a lot of sound problems with Windows 10, in fact it's the only thing that's really driven my up the wall.
I ended up, giving up on my Sound Blaster card and switching to my on-board audio.
So it might help to know what sound card you are using etc.
But the first thing that I would try it to go to Device Manager (right click on the start button and select it), once there find your audio device and right click on it and choose Uninstall. If it asks if you want to remove the drivers for the device say Yes.
Reboot your computer and Windows will re-detect it, install it, and select the correct drivers for it.