[CentOS] Help with sound on Packard bell

Hello to everyone
I had a little trouble with my new laptop, I have a Packard Bell MZ380
laptop with Realtek High Definition Audio, I have installed CentOS 5 on
it, I have sound by the speaker but when I plug the headphone the sound
is over, I mean I have not sound by the speaker and by the headphones.
Can someone help me? What I have to do ????
I'll be waiting for help.
-- 
"Nuestra recompensa se encuentra en el esfuerzo y no en el resultado.
Un esfuerzo total es una victoria completa".
                                        Mahatma Gandhi
              (@ @)
   |------o00o-(_)-o00o----------|
   |Manuel Enrique Chávez Manzano|
   |manuel864 at gmail.com          | 
   |manny at cmc.cfg.sld.cu         |
   |GNU/LINUX User               |
   |#424754                      |
   |Using CentOS 5              |
   |-------ooo--ooo--------------|
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