Recently i bought DELL inspiron 14 and made it as dual boot with Windows Vista and Ubuntu 9.04 and faced a strange issue. I can hear sound Vista in headphone as well as speakers. But in case of ubuntu i can hear sound in headphone only and no speaker sound and the strange thing is that when i first boot windows and then boot ubuntu both the mic and speakers will work properly . But when i first boot ubuntu i can hear sound from the headphone only .After some googlesearch and forum posts atlast i sloved the issue.Didnt got the exact issue yet but got the solution 
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The log files of both working and non working sound in the system seemed to be the same 
. At last tried an experiment by upgrading the ALSA driver and this time it got worked. Now i can hear sound in mic as well as in speakers…:).Anyone facing the same issue can give a try on this fix.
cat /proc/asound/version
will give the ALSA version details, mine was Version 1.0.18 and i upgraded to Version 1.0.21
Upgradation details is avilable here :: Click