To adjust the volume for multimedia playback devices
Open Sounds and Audio Devices in Control Panel.
On the Audio tab, under Sound playback, click Volume.
In the Master Out dialog box, drag the Volume slider for the appropriate device up or down to increase or decrease the output 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.
If the Place volume icon in the taskbar notification area check box is selected on the Volume tab, and your sound card volume can be changed using software, a speaker icon appears in the notification area. You can then change the volume by clicking the icon and adjusting the slider.