For all actions you will need console cable and direct access to your router!

You can load device in rommon and set config-register to 2142, then reload device again. It will load into default configuration and by entering configure memory you will get into nvram-configuration mode where you can change your enable secret. Don't forget after that change your config-register back to 2102.

So steps in order:

1. Restart device
2. Press Ctrl+Z right after you see first boot messages
3. In rommon enter:

confreg 0x2142

reset

4. Boot. Device now with default config. Do

enable conf memory

5. Change enable secret
6. Change config-register back to normal boot

(conf-t)# config-register 0x2102 write

7. End up with reload

For all actions you will need console cable and direct access to your router!

You can load device in rommon and set config-register to 2142, then reload device again. It will load into default configuration and by entering configure memory you will get into nvram-configuration mode where you can change your enable secret. Don't forget after that change your config-register back to 2102.

So steps in order:

1. Restart device
2. Press Ctrl+Z right after you see first boot messages
3. In rommon enter:

confreg 0x2142
reset

4. Boot. Device now with default config. Do

enable
conf memory

5. Change enable secret
6. Change config-register back to normal boot

(conf-t)# config-register 0x2102
write

7. End up with reload