Audi/Mic problem for HP envy sleekbook 6-1125ea

Hi,

I have a probelm with audio and microphone devices on my HP Envy Sleekbook 6-1125ea. Though my laptop speakers work fine, my internal microphone (as well as any externals which I plug into it) do not work at all!

Also, when I open the sounds controls, it does not show any playback or recording devices (even they are not shown under disabled or disconnected devices!) ...

PS. I have an up-to-date windows 8.1 64-bit and all my drivers are up-to-date. Nevertheless, I still downloaded the latest audio driver from the following link and installed it, but still have the same problem!

http://h10025.www1.hp.com/ewfrf/wc/softwareDownloadIndex?softwareitem=ob-110794-1&cc=uk&dlc=en&lc=en&os=4158&product=5314708&sw_lang=

Any help would be greatly appreciated!!

Thanks in advance!