Do not worry, there is nothing wrong with your Speakers and Windows. It is just the configuration that is not appropriate.
The problem might be with the software you are using to play music. Try exploring the software and in the settings, make sure the surround sound is selected.
Also, check the sound card settings. Make sure that the sound card application (can be found in the Control Panel) is configured correctly and 7.1 option is selected.
Hope this helps.