1. Open the Device Manager.
2. Expand the "Sound, Video & Game Controllers" section.
3. Right click on "Realtek High Definition Audio" and select to uninstall.
4. Put a check mark in the option to delete the driver software, and then ok.
5. Restart the laptop and go back to the Device Manager and check again for a Realtek driver. Keep uninstalling & restarting until Realtek High Definition Audio no longer appears under Sound...Controllers.
Windows will have installed its native driver when it could not find the Realtek files during the re-start. Sometimes it takes more than one attempt for this process to happen, because sometimes there are files for additional versions of the Realtek driver on the hard drive and they have to be removed one version at a time.