You need to install your Audio drivers.
Trouble shoot Audio Problems.
1) -Make sure speakers are not muted.
2) -Make sure Windows Audio Service is set to Automatic & Started. (Run services.msc) Scroll down to Windows Audio Double click, start the service. And it should be set to "Automatic"
3) -Download & save to your desktop, Audio drivers for your computer model and Operating System from your Computer MFG Site. (Do not Install yet)
4) -Uninstall Audio Drivers in Device manager & Reboot.
5) -When new hardware is detected, point to desktop for drivers.
Note: If you have PCI sound card installed, google the manufacturer of it.