Watchdog in Arduino Library - or at least support by bootloader

thank you

so question still stands,

I have the off the shelf Arduino IDE, program via the ide / code on the standard arduino boards,
standard boards etc,

I guess like, most people.

do we have an example design I can download, modify and use ?
are you saying I need a different set of boot loader and programer for the arduino ?

A guide would be good please.