From control panel, remove old realtek sound software/drivers.
Then download and install this driver
http://www.realtek.com.tw/downloads/RedirectFTPSite.aspx?SiteID=1&DownTypeID=3&DownID=558&PFid=23&Conn=3
Restart the system.
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If it didn’t work, reinstall using the following methods
Right click on the setup.exe file and select
Troubleshoot compatibility.
Then click on
Try Recommended settings. Then click on S
tart the program .
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Once installed, also try to run
Windows update from StartMenu>All Programs
Click on
Check for updates on the top left. Once the checking is finished, click on
Optional updates are available. Can you see realtek on the list? If yes,
tick it and Click
Ok. Once installed, restart your system.