Hi and thanks for using JustAnswer. My name is Eric and I will do whatever I can to help answer your questions and get your problem resolved!
There can only be one of two things wrong here. Either its an issue with the sound/audio input files in your system kernel, or its an actual hardware failure.
If its related to the OS or the kernel, we can resolve it by resetting the device. As long as you have a Google account synced to your device, your contacts, calendar, etc. will be re-synced to the device after you run the initial setup again as long as you sign in with the same Google/Gmail account.
I do recommend you go to gmail.com on your computer and click on the contacts link, then check all your contact groups to make sure the contacts are synced(if not, ask me about contact backup instructions).
Any apps you have, you can also get back after you reset the device by opening the Market, pressing Menu on the phone and choosing "My Apps". As far as any data that is stored on the SD Card(images, music, etc.), it will not be erased. Only the phones internal memory is formatted.
To complete a Factory Reset follow these directions:
- Open the Settings App
- Choose Privacy
- Choose Factory Data Reset
If that doesnt work, then its a hardware failure and the only thing left here is to take the phone to your carrier and request a replacement due to hardware failure. Unfortunately, this would be the only option left had the original reset not resolved it.
If you have any further questions, please feel free to let me know
...Please press the Accept Button(and the Smiley Face if prompted )
if I have helped you today so I am credited for my time assisting you.
Pressing Accept does not cost you any more, and only by you pressing accept am I compensated. Please don't leave negative feedback, If something isn't working let me know and I will continue working with you to resolve it! Positive Feedback and Bonuses are not expected, but are always appreciated!