Why won't my S4 charge in the USB port I am trying to charge my Galaxy S4 in my laptop but no matter which USB port it is in it will not charge. It is completely dead now. I am abroad and the adapter doesn't charge it either. HELP!
At first glance I can see (at least) one of the following problems:


The phone's "charging system" is dead(worst case).
Cable/charger is broken
Battery is dead.


Of course I cannot deduct something more precise, because of the lack of information you provide, but what I would do is the following:


Ask someone to lend you a micro usb cable to try charge it(use both wall plugs along with adapter and a PC usb port).
If the above wont work, take it to a local electronics shop to test your battery.
If the above fails too, you are probably unlucky.