How To Remove, Clear, Reveal, Unlock or Reset BIOS Security Password

If you can boot from CD/USB

When Windows doesn’t boot properly and you cannot get into the BIOS to change the boot order, you could be lucky enough that booting to CD or USB might already be set at a higher priority than booting to Windows and simply inserting a CD or flash drive will boot to it automatically. It’s also possible that CD or USB booting could be just below hard drives in the order, in which case you would need to temporarily disconnect the hard drive(s).

If you can still access Windows, another solution to enable CD/USB booting is using a great tool called Plop Boot Manager. What it does is allow booting from these devices even if the system BIOS doesn’t support the function or the boot order is not accessible. Even if you don’t want it for this purpose, Plop is a great tool to know about for using on older computers.

Here are some tools which can be used by booting from the relevant CD or USB flash drive. Simply burn the downloaded ISO file to a disc or use one of these ISO to USB tools.

PC CMOS Cleaner

PC Cmos Cleaner

PC CMOS Cleaner is able to recover, remove, decode and display the user or supervisor password stored in the BIOS irrespective of the machine brand. Award, American Megatrends (AMI), Compaq, Phoenix, Samsung, IBM, Compaq, DTK, Thinkpad, Sony, Toshiba are all in the list of supported BIOSes so there’s a good chance your BIOS is included. PC CMOS Cleaner is a bootable Linux CD so you don’t have to worry about operating system compatibility. On launch the program will first try to decrypt and display a list of possible passwords. Failing that, you can choose to remove the password using two options, the second of which will completely reset the BIOS to defaults so you’ll have to go and reconfigure it afterwards.

Download PC CMOS Cleaner

CmosPwd by CGSecurity


This is one of the more up to date and popular CMOS decryption tools although it’s still quite old dating back to 2007. CmosPwd decrypts the password stored in the CMOS and displays it. The following BIOSes are supported:

  • AMI WinBIOS 2.5
  • Award 4.5x/4.6x/6.0
  • Compaq (1992)
  • Compaq (New version)
  • IBM (PS/2, Activa, Thinkpad)
  • Packard Bell
  • Phoenix 1.00.09.AC0 (1994), a486 1.03, 1.04, 1.10 A03, 4.05 rev 1.02.943, 4.06 rev 1.13.1107
  • Phoenix 4 release 6 (User)
  • Gateway Solo – Phoenix 4.0 release 6
  • Toshiba
  • Zenith AMI

With CmosPwd, you can also backup, restore, erase or even kill the CMOS. CmosPwd is included in the Hirens Boot CD DOS programs menu. Select “9. Next” -> “2. BIOS/CMOS Tools” -> “2. BIOS Cracker 5.0 (cmospwd)”. There’s also a version you can run from within Windows which is available on the CGSecurity website along with some useful information.

!Bios by eleventh alliance


!Bios is a tool that was developed for a brute force attack on BIOS passwords. You can also backup and restore the BIOS and there’s even a Blaster option where can blank certain parts of the BIOS in the hope of removing the password, a powerful and potentially dangerous option because it could completely corrupt the BIOS. !Bios can try and crack the passwords used in some common BIOSes including various versions by IBM, American Megatrends (AMI), Award and also Phoenix. It’s a very old tool dating back to the late 90’s so is unlikely to work effectively on more recent computers.

Like CmosPwd, !Bios is also included in the Dos Programs menu of Hirens Boot CD. Select “9. Next” -> “2. BIOS/CMOS Tools” -> “4. !BIOS 3.20 (ibios)”. You can also download a separate !Bios Windows tool.

Invalidating the CMOS Checksum Manually

If you prefer to do it manually rather than relying on automated programs or the other tools like CMOS De-Animator aren’t working, it is possible to reset the BIOS password by using the debug.exe tool which will invalidate the CMOS checksum in a similar way to CMOS De-Animator. This can be achieved by typing two commands into the debug tool if you first boot up the computer in FreeDOS. Here are the instructions.

1. Install FreeDOS on a USB flash drive using Rufus or UNetbootin.

2. Download the debug.exe tool and save it to the root of your USB flash drive.

3. Boot up the computer with your USB flash drive and type the following commands: (take note that the second and third commands start with the letter O and not the number zero.)

o 70 2E
o 71 FF

reset bios password with debug

4. Restart your computer with Ctrl + Alt + Del and you should encounter an error message like “CMOS checksum error” which is normal. You can now access the CMOS setup without entering a password.

83 Comments - Write a Comment

  1. itinnovation 1 year ago
  2. Al 2 years ago
    • HAL9000 2 years ago
  3. loco bennelii 2 years ago
  4. Adil Radoncic 2 years ago
  5. Julie Bernard 2 years ago
  6. jaxonpalmer 2 years ago
  7. demethriuz galang 2 years ago
  8. Yvonne 2 years ago
    • Erock 2 years ago
      • David 1 year ago
  9. Ehtesham 2 years ago
  10. Mohamed 2 years ago
  11. Rene 2 years ago
  12. Ulises Gutierrez 2 years ago
  13. Collin 3 years ago
    • Collin 3 years ago
  14. cl dickinson 3 years ago
    • Rob 2 years ago
  15. IABROS 3 years ago
  16. zubair Mundasseri 3 years ago
  17. dan 3 years ago
  18. Peter 3 years ago
  19. Peter 3 years ago
  20. All Wilson 3 years ago
  21. Cliff Cook 3 years ago
  22. John 3 years ago
    • HAL9000 3 years ago
  23. ikhsanul 3 years ago
    • HAL9000 3 years ago
  24. Taikhoan 4 years ago
  25. bubble 4 years ago
  26. Jay 4 years ago
  27. Leza 4 years ago
  28. Akahee Nathaniel 4 years ago
    • Teews 3 years ago
  29. ayanda 4 years ago
  30. Lisa 4 years ago
    • Hans 4 years ago
  31. xaris 5 years ago
  32. Usmik Saha 5 years ago
  33. Notpil 5 years ago
    • DrJasonThomas 5 years ago
    • russ 5 years ago
    • Fachri 5 years ago
  34. Bright 6 years ago
  35. 4bigana 7 years ago
    • malc 7 years ago
  36. Pablo 7 years ago
    • kaki 6 years ago
  37. WNantes 7 years ago
  38. Benjamin E. Nichols 7 years ago
  39. BGM 8 years ago
  40. Tony Joseph 8 years ago
  41. Ikem 8 years ago
  42. erwin 8 years ago
    • HAL9000 8 years ago
  43. Zaven 8 years ago
  44. Geeboy 8 years ago
    • HAL9000 8 years ago
  45. jahangir chauhan 8 years ago
  46. raymond 8 years ago
  47. Prince Dalieh 8 years ago
  48. nathan 9 years ago
  49. Jozef 9 years ago
  50. Stephen Highzeek 9 years ago
  51. sameer misger 10 years ago
  52. shraddha 10 years ago
  53. Josh 10 years ago
  54. Persia 10 years ago
  55. Dragos 10 years ago
  56. mino 10 years ago
  57. deza 11 years ago
  58. arjun 11 years ago
  59. Amirz 11 years ago
  60. Gaara 11 years ago
  61. jaymanjula 12 years ago
  62. digArt 12 years ago
  63. Roy Raay 13 years ago
  64. bhasidh 13 years ago
  65. chunky 14 years ago
  66. Ammar 14 years ago
  67. MR7 14 years ago

Leave a Reply

Your email address will not be published. Required fields are marked *

Note: Your comment is subject to approval. Read our Terms of Use. If you are seeking additional information on this article, please contact us directly.