Screen Display Shows Fastboot And Mobile Is Not Responding To Any Key Xiaomi Redmi Note 3

Chosen Solution

Mobile display shows FASTBOOT and mobile is not responding.

Hold the power button for 10 Seconds. Your device will reboot itself.

Leaving your phone in Fastboot for 1-2 minutes should make it reboot itself.

just press on to volume up button and power button for about 30 seconds

According to what i know, your phone is in a mode called EDL (Emergency Download). I think the ROM got corrupted, so a reflash should fix it. By reflash, i mean to flash a copy of the stock ROM (I dont recommand custom or root ROMs).