No sound device installed

I have a Lenovo G510 laptop running Windows 8.1, 64bit. Sound worked when I first purchased it a week ago, but now I get and error stating that "No sound device installed". I went to Device Manager and the only device is for the Bluetooth. There is not any other audio device listed.
I know that it is still under warranty, but I would like to fix it myself if possible. I have been in contact with Lenovo Tech Support and they are working to see what the problem is, but it's taking too long.
Any help is appreciated.