Hmmm... that is definitely a software issue in my case. Well, if it is a hardware, then it shouldn't work by just a simple restore. Try doing a system restore to the nearest safest point in order for you to assess if it is a software issue. Here is a more informative material for you as well:
http://thepcguyz.blogspot.com/2014/09/how-to-fix-your-sound-if-it-only-works.html
http://thepcguyz.blogspot.com/2014/09/how-to-fix-your-sound-if-it-only-works.html