cisco 2811 reset factory with putty

۱٫ Connect to the serial console.

۲٫ Power off the router and then power on.

۳٫ Send the router a BREAK. This should bring you to the rommon prompt

۴٫ Type this command at the rommon prompt in order to boot from Flash.

  rommon 1 > confreg 0x2142

۵٫ Reset the router.

  rommon 2 > reset

۶٫ The router should now boot into the Initial config dialogue:

  Would you like to enter the initial configuration dialog? [yes/no]: yes

۷٫ Follow the prompts, to set a basic config.

۸٫ Enter enable mode and set the router to boot from the right place

 Router>enable
 Router>conf t
 Router(config)>config-register 0x2102
 Router(config)>end
 Router>wr mem

۹٫ Reload the router to check it worked properly