|Try plugging and removing the headset multiple times to burnish the contacts.|
Check Programs in Control Panel to see if any driver updates were installed since your sound worked correctly. You need to show Windows updates when in Programs and Features.
Try installing the latest drivers for your sound. You may need to remove the Realtek device from Device manager and then install the drivers from the link below without rebooting.
Disconnect all devices from the sound ports while performing this operation. After installing the new drivers check Device Manager to see if the devices are working properly, then reconnect your headset.