Download the second tool from here (Lumia Software recovery Tool)
FAQ - How can I recover/reset/restore my phone software? - Microsoft - USA
Turn the phone off... Or if it won't power down use the next Boot Cycle.
From power off hold the Volume Down button and plug it into a USB port. Hold that Volume Down button until it boots to a screen with a giant exclamation point on it.
Now use the Lumia Software Recovery Tool to flash a clean version of the OS and Firmware to your phone. Use the "my phone will not boot or respond" option.
Your Boot File has become corrupted.