Heya Azza,
Have you tried testing those speakers in another computer? I would bet that your speaker is just bad. There isn't much more to sound other than having the right driver and the balance being set in the middle.
If in device manager your sound card drivers aren't showing an exclamation mark or a red X, then they are installed ok. Then if the balance is set and you are getting sound but only through one speaker, then the other one is bad.
The only other thing to check is if your sound card has software running that has additional settings you can play with. Check your taskbar in the lower right hand corner of the screen and see if there is any kind of sound managers running (not the little windows speaker).
If you have no other sound manager installed, then I would be fairly certain the speaker is just bad. If it is a laptop, then the only thing you can do is plug in some external speakers, or deal with just having one. You should be able to set the sound to mono output somewhere if you just want to use one speaker.
Hope that info helps you!
