Set it as the default device because if there is 2 audio outputs active they will cancel each other out. Other than that have you tried turning it up? Because the have been issues when poeple have forgot.
This is something i found, it mght work or might not.
Open Device Manager by clicking the Start button , clicking Control Panel, clicking System and Maintenance, and then clicking Device Manager. If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
In Device Manager, locate the device you want to update, and then double-click the device name.
Click sound video and gaming controller
Open each audio controller in sound video and gaming (one at a time) and update by Clicking the Driver tab, and then click Update Driver and follow the instructions