If I may suggest a few basic things to check:
From what I could find on this model, it uses some sort of RealTek chipset for sound (but they're kind of vague about exactly which one), and it is capable of 5.1 channel Dolby output from its audio jacks, so, maybe try another one?
Do the built-in speakers mute when you plug in your headphones, or do they keep playing? If it's the latter case, you're definitely not in the right spot.
One question: does it have really have a built-in subwoofer? I bet that sounds pretty good for a laptop, huh?
Later On,
D
Possibly, that are again jacks with each of them having multiple functions

Just try some of the jacks (if the music doesn't stop playing on the built-in speakers, you can try another....)
@horusfalcon: my laptop also has a built-in subwoofer, and yes, the sound is not bad when you're in front of it (don't think the whole room can enjoy marvelous music)