IPhone 4 suddenly won't turn on - iOS 7 beta 6?

I've been using iOS 7 betas from 3rd party sources and it's been working great until suddenly it froze and I had to hard reset it. However after that it turned off itself and it's still unresponsive. I can't see if it's charging and it's nowhere in iTunes. I also tried setting it in DFU mode with no success. What can I do? Could it be the software locking us out or should I turn to hardware for that issue?

You may want to take it to an itstore and get them to force reset it for you, they may charge you quite a bit for it! There's no other answer i can think of for an unresponsive iphone!

You need to register your device's UDID with a developer account as soon as possible, through a site like http://www.udid.in/.It's $5, and then you also don't need to worry about Apple permanently disabling your device for running unreleased software.

Hold the home button and power button till you see the apple logo then let go. You usually have to hold it for 20 to 30 seconds