You need to reinstall your sound driver. Only you know what sound device (hardware) you are using.
What does it show in Device Manager, Hardware? Do you have a yellow ! showing by Sounds? If so, reinstall the drivers.
Last week I was using a utility to clean up my computer. In the process I acidentally deleted the sound device file. Song no longer plays on my computer even though the speakers, etc. are all correctly connected. When I open the control panel it says "No Audio Device." How can I fix this problem???