If you have low volume, try checking all the volume controls.
Your main system volume, the volume control on the speakers themselves, the other volume controls in Control Panel --> sounds and audio devices, and the volume control in whatever you are using, eg Windows Media player.
If you don't have some of those volume controls, don't panic. For example, there may not be one on the speakers.
And make sure the speakers are plugged into a speaker output (and firmly), some sound cards have headphone outputs which are much quieter and can look similar.
Hope this helps.