What if Win7 headphones don't sound?

The method provided here is applicable in this case, please ensure that headphones and microphone plug in the air is correct, and then ensure that the Win7 installed the correct sound card driver (generally normal installed after the driver, the tray on the right side of the taskbar to see a small horn, as shown in the following picture:

Right-click the small horn on the taskbar system tray and choose Play Device (P) from the shortcut menu.

In the Sounds window, in the Playback tab, right-click Speakers and choose Set as Default Device (D) from the right-click menu, and then press the OK button.

If your headset and microphone are plugged into the front panel of your computer and the settings above do not work, you can select the "Set as default communication device (D)" Item again in the window above.