The below details how to recover a Cisco router if you have forgotten the password of there is a problem with the configuration.
WARNING: By doing this you may loose any configuration on the router.
1. You will need to be physically connected to the console port
2. Turn the router off
3. Turn the router on while holding down CTRL and repeatedly pressing BREAK. If this goes well then you should get a message saying *** System received abort due to Break Key ***
4. At the rommon> prompt type confreg 0x2142 and press enter
5. Type reset and press enter, the router will now startup and ignore the saved configuration.
6. When prompted with “System Configuration Dialog” either select yes and run though the wizard or no.
7. At the router> prompt enter en and press enter
8. Type conf t and press enter
9. Type config-register 0x2102
If you want to keep your previous configuration and just change the password
10. Type copy start run and press enter to reload your previous config
11. Type enable secret <new_password> and press enter
12. Type copy run start and press enter
13. Type exit and press enter
14. Type reload and press enter to restart the router and check everything is working
If you want a clean new configuration
10. Type copy run start and press enter
11. Type exit and press enter
12. Type reload and press enter to restart the router and check everything is working