How do I default or reset a Cisco router?

Please see the regular process to reset the password on 1841 Router below,

  • Connect the console cable to Router 1841
  • Use the power switch in order to turn off the router, and then turn the router back on
  • Press Break on the terminal keyboard within 60 seconds of power up in order to put the router into ROMMON
  • Type confreg 0x2142 at the rommon 1> prompt in order to boot from Flash

This step bypasses the startup configuration where the passwords are stored

  • Type reset at the rommon 2> prompt.

The router reboots, but ignores the saved configuration.

  • Type no after each setup question, or press Ctrl-C in order to skip the initial setup procedure.
  • Type enable at the Router> prompt.
  • You are in enable mode and should see the Router# prompt
  • Type erase start¬†at the Router> prompt.
  • Type configure terminal.
  • Type config-register #config-register 0x2102
  • Type write memory¬†
  • Type reload

– See more at: https://supportforums.cisco.com/discussion/11607366/how-reset-cisco-router-1841-password#sthash.keYSGsUX.dpuf