Main menu:
Sound & Video
Follow the steps.
Go in to your realteck sound card management and follow the screen shots below
Click on playback
Then go over to the right hand side,
you will see two little arrow click on the one on the right
Just below the rear pink in is a little box click on it for advanced
You will then see advanced settings put a tick in microphone boost and click OK,
you will then be able to alter your microphone to a satisfactory level.
Sub-Menu: