Please check the following, Right click the speaker icon on the taskbar and choose the Playback Devices, the Sound window will open like this.
Make sure the Device Usage is Enabled at the bottom of the window, next click Levels tab at this window
Check whether the speaker is working or not, click it, then click Properties, the next window will open
In the Levels window make sure the PC Speaker level is set all the way to the right and the speaker is on
Hope it's helpful.