Ok someone upluged the computer speakers power cord and now i have no sound and yes i did plug the power cord back in just so yall know.
The problem is my speaker icon in the bottom right hand screen says i have no audio output device installed .So i went to sound and in playback it has no audio devices are installed.Then i went to device manager and to sound,video,and game controllers and i have realtek high definition audio and it says the device is working properly. I updated and it and it still doesn't work and i downgraded it and it still doesn't work. i've exhausted all my resources and it has me stummped and now im in need of help.

thanks for the help man but i got it fixed now it turned out that my speaker wire was not plugged up to the right port in the back and it made my speaker message say that there was no audio device installed, but thanks for the info though.