Info-Mac

my iphone 3gs worked perfectly last night. It was plugged into my laptop the whole night and therefore was charging the whole night. and some songs were transferring.
but when I woke up, the laptop was still on, itunes were not recognizing the iphone and iphone was turned off. I tried to turn it on but no apple sign, just black screen, i tried to access the dfu mode, but nothing happened, i tried it plugged in, plugged out, tried to hold both keys, each one, for a long time, all the combinations i could imagine. still, nothing happened. i followed the instructions on how to enter dfu mode, i did exactly as i was told, and still nothing happened, itunes didn't react nor they didn't even recognize the device...
can anybody please tell me what's going on??? i worked perfectly 10 hours ago

I managed to turn it on just a few minutes ago, DON'T EVEN KNOW HOW :S , but I'm scared that everythime when it turns off, the same will happen and I'll have to try and try and try not knowing will it ever even start again.
and I don't even know why it turned itself off last night without empty battery reasons or any other known reason...

battery is fine, just to mention, now it's on 97% and it's going down slowly so I don't think that battery is the problem.
also, I'm running on iOS 6.0.1...
thanks

Just now, I turned the iphone off just to check will I be able to turn it on again, and the same problem happened, I can't turn it back on

Again, It turned off last night and I can't turn it back on since then... and when I connect it to itunes, nothing happens.... when I connect it to wall socket, still nothing. no access to dfu too.

I would also like to mention that when I did manage to turn it on (yesterday), it took about a minute or so until the apple logo FINALLY disappeared and turned my phone on.

Can it be that the iOS 6.0.1 is simply too overwhelming for my 3gs?

Pleeeease help, come on people, I'm desperate over here !

Has the phone ever been Jailbroken or otherwise hacked? On any of the occasions that the phone was able to turn on, did it look like the battery was able to take a charge? The next time the phone manages to turn on try connecting it to iTunes and restoring it as a new phone.

I have friends using a 3gs and iOS 6.0.1 without ant problems so I doubt that's the problem.