Left-click the speaker icon in your Notification area once to open the volume control. Then, use the slider to adjust the volume level.

Double left-click on the speaker icon in your Notification area to open the Volume Control Mixer Panel (see above).

Right-click the speaker icon in your Notification area. Choose Open Volume Control to also open the Volume Control Mixer Panel (see above).

Right-click the speaker icon in your Notification area. Choose Adjust Audio Properties to open a volume slider bar.

Click Start > Control Panel, and click Sounds and Audio Devices. In this window you will also see the device volume slider bar.