Recently, while playing unreal tournament, I realize there was no sound coming out of the speaker once I unplugged my headphones. I restarted thinking that it would fix the problem, but that didn't help, so I decided to uninstall and reinstall the sound driver from realtek, no good either. Finally I deicided to reformat my computer using the recovery partition. Reassuring myself that this will definitely solve the problem I was shock and confuse as to why no sound came out of the speaker after the recovery. After going to the Realtek sound control panel I realize that the computer thinks or detected that a headphone was plugged in when clearly it wasn't. The sound does work with the headphone in and I am sure the speaker is not damaged because the POST sound, "boommmmm", comes during bootup. I really don't understand what is going on, and I already reformatted the harddrive 2 times.

I have read that the problem can be temporarily solve by replacing the motherboard, but after about a week or two, the same problem will arise. I have also read that other brands including HP, DELL and Sony has similar problems.

I can live without the speakers but I am not sure if further problems will persist with this laptop, since its only been month that I have purchased it.

Thanks for many reply/help.

Just some real quick ideas

Speakers plugged into power outlet and on
Speakers plugged into back jack securely
(actually if you heard the startup booom sound, then they must be)

Sound volume up on speaker
Sound volume up on Windows
Sound volume up in the game that you are using
(That might be it)

If you play a song (through Windows media player) can you hear it ?
If so this must be an in game setting (ie mute sound) Please check all settings in the game.

I actually have a laptop, and I am pretty sure the speakers are working and window does display that sound is coming out, but for some reason the system is stuck in a headphone mode.

Actually that is a setting in Control Panel - > Audio and sound

Somewhere in there it says Speakers=Headphone

This may be in the sound software program too, check in the all programs list for that.