To reset a Cisco router to factory default

To reset a Cisco router to factory default (removing the startup configuration file), perform these steps:

1.To erase the configuration file, issue the erase nvram:command. Reload the router by issuing the reload command.

2.If this does not solve the problem, attempt to break into ROM Monitor (ROMmon) by issuing the break sequence (usually Ctrland break from the Hyperterminal) from a console connection.

Refer to: Cisco Standard Break Key Combinations. You should see this ROMmon prompt:

rommon 1>

3.Change the configure register value to ignore the startup configuration by issuing theconfreg command, as shown in this example:

rommon 2> confreg 0x2142

4.To reload the router, issue the reset command, as shown in this example:

rommon 3> reset

5.After the router boots, issue the enable command at the Router > prompt. The prompt changes to Router#, indicating that the router is now in privileged mode.

6.To enter config mode, issue the config terminal command. You should now see aRouter(config)# prompt.

7.To change the configure register to recognize the startup configuration, issue theconfig-register command, as shown in this example:

Router (config)# config-register 0x2102

To break out of configuration mode, press Cntl and Z. To save the blank configuration, issue the copy-running config-startup config command.