If you are not getting any sound from Windows 7, first check your system volume and then check that all connections to devices are secure. Next, try checking your hardware, such as your sound card or sound processor. Finally, try updating your audio drivers.
The first step is checking the system volume by clicking Start, then Control Panel, then Hardware and Sound. Under Sound, click Adjust System Volume. If the volume isn't the issue, check that the cords connecting all sound output devices such as speakers or headphones are secure.
If this doesn't resolve the problem, check your sound card by clicking Start, followed by Control Panel and then System and Security. Under System, click Device Manager. Double-click on Sound, Video and Game Controllers. If a sound card appears there and there is a yellow question mark next to it, right-click the sound card, click Properties, choose the General tab and look under the Device Status box. This may tell you the issue with the sound card; many times it is simply a matter of having to update the sound card driver.
Updating your audio driver may be the solution. You can use Windows Update to update any drivers automatically. If your device needs a third-party driver, you can usually locate the latest driver on the sound device's manufacturer's website. Download the driver and reinstall it manually.