I have an iPhone 3G updated to 3.1.3, and every once in a while when I try to turn it on or when I try to answer a call, it will crash and I will have to hard reboot it. When it reloads, nothing will play. Everytime I try to listen to a voicemail or play music or anything else, it unpauses, then immediately goes back to paused without playing any sound. I can make calls, but when they are answered, noone can hear me and I cannot hear them. Speakerphone will not turn on either. Even the alarm and timer on my phone do not produce sound, only vibrations. I have tried resetting all settings, restoring it, restoring it as a new phone, etc. and nothing will work. The only thing that works is when I turn it off and back on by holding down the Sleep/wake button, and then every once in a while it will reload with audio again (but this usually only lasts for a couple hours before it crashes again).

I have read a thousand posts and cannot find anyone who has the same problem as me, and have not found any solution. I took it into the apple store and they didn't know what to do either (and its out of warranty by a few months). Is there anyone who knows what could be the problem (and how to fix it)?!?!