Sound working in Headphones but Does not work in Laptop Speakers

Hi I own a Hp Pavilion Dv6z-2000 Windows 7 Home Premimum (64 bit)

 My laptop has encountered a lot of Driver problem in the Usb ports and the Sound drivers.. I have managed to fix all of them and all drivers seem to be installed correctly. But when I try listening to something with my speakers no sound comes out. But when I try listening to something on my headphones it comes clearly with a little bits of cracks (might be because my headphone is old). I am really frustrated and really hope to fix this. PLZ HELP 

                                                                                                                      Thanks, HpFan2000