Conexant audio device wont install

Hello, one day when i turned on my laptop, i could hear a difference in the sound like it sounded lower than normal. i tried everything to fix it back, but nothing worked. then i went online and downloaded the conexant audio device, i opened it and after a while it would say that it failed to install. it said that there is no audio device on my computer. i kept trying over and over but it does the same thing. there is this red x on the volume icon and it says no audio output device is installed.

i need help asap! no music wont play and videos wont even open!

i have a Toshiba windows 7 laptop