Delete / Erase Password on Cisco routers keeping the config

Step 1: hit ctrl / break directly after powering up the router.

    If the break sequence does not work, refer to Standard Break Key Sequence Combinations During Password Recovery 
    for other key combinations. 

Step 2: type: confreg 0x2142 from rommon 1>

Step 3: type: reset from rommon 2>

Step 4: Would you like to enter the initial configuration dialog? [yes/no]: answer NO

Step 5: type: en from router>

Step 6: type: COPY STARTUP-CONFIG RUNNING-CONFIG from router#>

Step 7: type: SHOW RUNNING-CONFIG from router#>

Step 8: type: CONFIGURE TERMINAL from router#> to remove any existing passwords enter Global Configuration

Step 9: type: NO ENABLE SECRET from router (config)#>

Step 10: type: NO ENABLE PASSWORD from router (config)#>

Step 11: type: CONFIG-REGISTER 0x2102 from router>

Step 12: Return to Privileged Exec by hitting the CTRL Z keys

Step 13: type: COPY RUNNING-CONFIG STARTUP-CONFIG from router>

Step 14: Reboot the device