Cisco Router Password recovery
Step 0. Plug console cable to the router
Step 1. Power cycle the router.
Step 2. Send a "break" command to the router within the first 60 seconds after power cycle. From the console mode, press "Control /Bracket" or "Control/Break"
Step 3. From the ROM monitor prompt, set the configuration register value to 0x142. This causes the router to bypass the configuration contents stored in NVRAM upon next bootup. To do this, type:
> o/r 0x142
Step 4. Once the configuration register has been changed, initialize and reboot the router by typing the following:
> i
The router will reboot itself.
Step 5. After the router boots up, you will be prompted if you want to enter the initial configuration dialog. Type: "n" for no. Note: If you accidentally enter the initial configuration dialog, abort by typing: .
Step 6. Enter privileged EXEC mode by typing the enable command. No password will be required. The prompt will change to Router(boot)#.
Cisco Router>enable Router#
Step 7. Load the original configuration back into the router.
Cisco Router# copy startup-config running-config
Note: If the router has originally been configured with a hostname, the prompt will now change to router_name#
Step 8. Set the new enable password.
Cisco Router# config term
Cisco Router(config)# enable secret
Cisco Router(config)# enable secret
Step 9. Restore the configuration register and exit configuration mode. The configuration register must be reset so the router will properly boot using the configuration now stored in NVRAM.
Cisco Router(config)# config-reg 0x2102
Cisco Router(config)# end
Cisco Router(config)# end
Step 10. Save changes
Cisco Router# copy running-config startup-config
Step 11. Reload the router
Cisco Router# reload
Reference : http://www.cisco.com/en/US/products/sw/iosswrel/ps1831/products_tech_note09186a00801746e6.shtml