On windows 7, you can find just about anything by typing in the search box. Click on the Windows (start) button and type 'volume' in the 'Search Programs and Files' box. Links to volume control will appear. This search facility in Win 7 is very robust and can help you find just about everything you're looking for. Very handy. Helps when you're getting used to this OS.
Additionally, at the bottom right in the taskbar's service tray, you should have a speaker icon. If you left click on this, you can adjust the volume by click+dragging on the slider.