Stereo mix issue with audacity

I have been using audacity for a long time on my other computer, i just got this new computer and got it on here when I tried to record with it i can barely hear the music but i can hear my own voice and when i change it to stereo mix on audacity i hear the music but not my voice. I have never had this problem before and with the new computer i am having it.

I have a HP with win 7
stereo mix is enabled as well as my mic and i have set stereo mix to default like i did with the other computer im unsure why it is not working right can you help me please?