I corrupted my bootloader on one arduino, luckily I had a spare lying around. Please help as there is not a single tutorial to help my exact state
I have a page about programming a bootloader using another Arduino.
Basically you grab the code from here and then make up wiring from the good device (which you put the sketch onto) to the device to be programmed, like this:
Arduino Nano Target Nano D10 (SS) Reset D11 (MOSI) D11 D12 (MISO) D12 D13 (SCK) D13 Gnd Gnd +5V +5V