My best guess would be you need a driver update. so i will work with the information i have.
firstly to determine it's the driver do as follows.
1. click start
2. right-click on computer
3. click properties
5. click device manager
check for any unrecognized devices (usually have a yellow asterisk next to them, and are listed under other devices)
if this is the case. go to your computers manufacturers site. search under support for drivers, and select your model. under audio should be a driver for your computers device. download and install it.
You could also download the free version of SlimDrivers. This program can identify, download and install the latest versions of all device drivers that you computer needs. just Google SlimDrivers for a download location.
You could also try reverting the audio device drivers to the old driver that worked.