No matter what you do, you can't get your phone to turn on.
Hold end button/power button on. If this does not work try removing the battery and then put the battery back in. Is your phone charged?
Make sure that the outlet your charger is plugged into is working. Check to see if the charger is plugged in all the way and is inserted properly. Make sure the phone is off while charging.
Check to see if you have the 3G symbol in the upper right corner and have bars available. If you have 3G and signal bars, then restart your phone.
This could be because someone might have spilled something on the speaker area. To fix it you will have to dry it out with hot air. If that does not work you will have to replace the speaker.