I've had the phone on charge all night and this morning it still wont turn on. It does all the usual start up things... but as soon as it looks as if it is ok it turns itself off again...

Sometimes "intelligent" chargers will not start charging if a battery is too flat, but usually there will be at least a light showing that there's power to the charger.
You could try jumping a good battery across the one you want to charge to get things going (+ve to +ve, -ve to -ve).
If it's broken it's usually worth a look if you can get it apart. Look for a blown fuse, bad solder joint, wire broken, something burnt out etc. You might be able to fix it.
Don't plug it in while it's apart unless you are certain that nothing will short out and that you will not touch any live wires!

Before you trouble shoot a car always charge your battery. It sounds like you have a loose Battery Cable to the Starter to me. This has happen to me that's how I know. To confirm this pull on the positive battery cable while someone else tries to start your car. Did it start? If it did not start then it's between your Battery and your Starter. Let's now check your Battery. Fully charge it again and make sure you have 12.6 Volts if your Battery does not take a charge it has a bad cell and needs changing. If your Battery turns out good then you have to check your starter or Solenoid and if one is bad change them both. Remove it and have an auto store check it to see which one is bad. I hope this helps you out. Let me know how you make out.

Hello,
Sir looks like its the fault of your phone, Did you rooted your phone ever, if no then please try to open it's boot menu, by pressing the power button and volume down button, and then restore your phone. This will help you.

maybe your battery or your phone os .... try a new battery if nothing happens... try re flash your phone

Try leaving the battery in with it charging all night, if the phone won't turn on after that, you'll need to exchange it.

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Chances are your phone got too hot during the night and overcharged the Lithium Ion battery. If those batteries are exposed to too much heat then they won't have the battery life they used to have. You need to purchase a replacement battery or contact your wireless carrier to see about getting another one.

check the battery and charge and also the water solution of the battery .then charge the battery.Then check for loose wiring .

make sure that your charger is not bent, i had the samd roblem sometimes you just have to get a new charger or just get that one to position right so that it will charge the phone

In the settings you have a option that will set the default factory settings.