To change the system sound volume
Open Sounds and Audio Devices in Control Panel.
On the Volume tab, under Device volume, drag the slider right or left to increase or to decrease the system volume.
To open Sounds and Audio Devices, click Start, click Control Panel, click Sounds, Speech, and Audio Devices, and then click Sounds and Audio Devices.
To mute sound volume, select the Mute check box; to restore the sounds, clear the Mute check box.
If you select the Place volume icon in the taskbar notification area check box and your sound card volume can be changed using software, a speaker icon appears in the notification area You can change the volume by clicking the icon and adjusting the slider.
The Device volume slider on the Volume tab is linked to the volume slider in the Volume Control dialog box. Changing the system volume on the Volume tab also changes it in Volume Control, and vice versa.