No Sound from laptop speaker on Windows after installing Ubuntu

[thehacker]

Hi,
Few days ago I installed Ubuntu on my system as dual boot with Windows Vista Home Premium. It works fine and I am able to hear sound from my laptop speaker on Ubuntu. But on Windows I can only hear something through headphone, no sound from laptop speakers - even when all the headphone and other jacks are removed. I tried some settings but it dint worked...
Need help
Thanks in advance
Regards,
Aki