If you forget or lost your cisco password, following are steps to recovery.
1. Press CTRL+PauseBreak when router is processing POST.
2. Write confreg 0x2142. Confreg 0x2142 will not copy startup configuration when POST.
3. Write Reset for reset your cisco.
4. write enable on cisco prompt. You wil not your password cisco. Because cisco not to read starup config.
5. Enter to config mode.
6. Copy startup config to running config (nvram to ram).
7. Change your enable password.
8. Change config-register with 0x2012
9. Save your configution.
10. Restart your cisco with Reload Command.
11. Please login to your cisco with new login.