when i plug in my headphones or mic my PC wont show a pop up message?

my pc wont show a notification telling me i have pluged in my headset, i am trying to use my mic-build-in kind of headset. when i plug it in nothing happens is if i never had plug it in, my headset also does not appear in my playback devices, shows as 'not plugged in'
my headset is the kind where it has the mic and headphones divided into two plugs connected to the rear of the PC.
i am using windows 7 home premium 64-bit with REALTEK.

yes i am sure everything is connected and volume is okay. I was playing an online game and i could hear what people were saying but not speak, after i umpluged and pluged back my headset i found 'stereo mix' to be in the wrong tab, see pictures.

turns out that after installing everything in the right place (even tho i dont know why stereo mix is now under the recording tab) you ALWAYS have to re star your computer, even small changes like 'eco-ing' your mic wont always work properly if you dont re star your computer, shutting it down didnt work for me so always re start it, seems like its even faster. any similar problems please post it here, i like learning about this things and ill figure it out for you.