Check that audio is started in services..
Go to Start>> Run>> type in services.msc.
A window will pop up with a list of services. Scroll down to Windows Audio>> Right-click>>Properties.
Make sure that 'Startup' is set to automatic. Click Apply and okay...Now check the startup status under services..Make sure it says started. If not look to the left and click start service...If the service is already set to automatic..turn it off click apply and okay..then set it to start..click apply and okay..
Check device manager and make sure the drivers are downloaded and have no conflict
Right click on 'my computer'..Click 'manage'...Click 'device manager'...Check for audio drivers...If you see a red X..the driver is disabled ...A yellow ! means there is a conflict....The following link will walk you through how to use device manager...Windows Device Manager