1, put a tick in front of the "Optimize windows Sound and Audio Configuration" option of the Optimizer, which will result in no sound on and off. Remove this tick and try it (if you have this software).

2. Try the following methods:

Start/run/enter regedit, open the registry editor, find the branch of [HKEY _ Current _ User \ Control Panel \ Voice], and change the key value of subkey Beep from No to Yes.

3. Open the Control Panel/Sound, Language and Audio Devices/Sound and Audio Devices/Sound/Select the "Windows Default" setting in the sound scheme drop-down list and press OK.

4. If the fault still exists, please restore the system or reinstall it.

Use the system restore method that comes with the system:

System Restore: Start/Programs/Accessories/System Tools/System Restore, click Restore my computer to an earlier time, and then click Next. You will see that the date page has a dark date, which is the restore point. After it is selected, click Next to restore the system (Win7), and then select the device and security sub-options in the control panel.