HP laptop no sound from speaker but there is sound through headphone

My wife HP Pavilion DV6175ea laptop running windows 7 ultimate 32 bits was fine with the sound until a month ago. Note that upgraded from vista since the windows 7 launch.
From that date till now it as no sound from the speakers but it is ok from the headphones.
Tried different audio drivers but no results.
Tried to insert and remove headphonde jack several times with no results.
Any ideas of what can be the problem?
Thanks,
Jorge

Laptop speakers are generally very delicate and if played on full volume can be blown very easily. My Dell Vostro's right speaker has gone like that while I was watching a movie on VLC player with volume more than 100%. So people using VLC player, should be careful with the sound controls within the player. This is my experience with laptop speakers. I hope you did not have this problem.

On the system tray right click on the speaker icon, select Playback devices.

On the opened Sound Dialog box, make sure that Speaker icon has a green check mark as shown below. Click on Configure button and test the speakers working or not. Complete the speaker setup and close the dialog box.

Check the properties and make suitable adjustments in available tabs.