Urgent help required. Updating software for a relative's new Samsung Galaxy 4 and all went well till reboot and now it is completely dead! Black screen, no ability to turn it on - nothing! Phone only one week old!
Plug it in. Make sure it has a charge. Wait. Some updates take longer than you might think. It might start on its own if you leave alone for an hour or so. Just be patient. If it doesnt finally start you might try booting into recovery.