Reset BIOS Password 11


I spend my days supporting an extended network of over 350 machines. When I had an upstanding user forward me this information, I almost took a load in my pants. I lock my BIOS’s to ensure no one can tamper with information on my machines. I use it to make sure unauthorized individuals can’t start my machines up.

This makes it all useless.

A simple DOS trick resets (deletes) your motherboard BIOS (CMOS) password, to grant access to your computer and/or BIOS Setup. In Windows 9x you can drop to dos, boot from a win9x floppy or reboot to the native MS-DOS mode, using the “Command prompt only” option from the Windows 95/98 Startup Menu (hold Shift and F5 at the same time while your PC boots).

Switch to the C:\windows\command directory and type:

DEBUG

and hit Enter. You’ll see a dash (-) at the DEBUG prompt. Now type:

o 70 2e

which will show as -o 70 2e at the DEBUG prompt. Hit Enter. Then type:

o 71 ff

and hit Enter. Finally type:

Q

and hit Enter one last time, to quit DEBUG, back to the C:\> prompt.
Now you’re ready to reboot your PC, and press the appropriate key or key combo (look it up in your motherboard manual if you don’t know it) to access your BIOS Setup. You’ll notice that the password is gone.

NOTE: This works only with the following MS-DOS versions: MS-DOS 6.00 – 6.22 and MS-DOS 7.xx (MS Windows 9x)

To stop it you’ll need to delete Debug.exe from your installation. Use a program like DeepFreeze to lock out key combinations during boot, and ensure that C: is your default first boot device.


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11 thoughts on “Reset BIOS Password

  • tim

    WinXP is safe then? I noticed that you havent removed “debug” from the installation.

    Where did you get that little piece of knowledge? Just wondering.

    What assembler instructions do “70 2e” and “71 ff” unassemble to?

    You can also reset the bios password (and the bios) by removing the CMOS battery and booting.

  • avery

    its just changing the value at memory location 70 to 2e (hex)
    and the value at location 71 to ff(hex for 255)

    this will not work on all computers because some bios manufactures store the info in other memory locations

  • JagEsquire

    1) Machines running XP can still have the password reset if you use a boot floppy with a copy of MCDOS 6.-7.

    2) Everyone can find everything is on the net

    3) “Avery” has it right The command changes two memmory spaces in the BIOS, change the numbers you use and wreck the BIOS

    4)No You can not reset the BIOS on new machines by pulling the battery. Give it a try.

  • Asadulah

    I have atoshiba lap top which i have forgotten the BIOS password . I removed the CMOS Battery but it didnt work it is still asking the password. if any ine can help me how to remove it
    thanks

  • ROBERT INGRAM

    HI I HAVE AN OLD RESEARCH MACHINES (UK)
    486SX 33MHZ THE BIOS HAS BEEN PASSWORDED SO I CAN’T GET INTO BIOS, I TRIED THE ABOVE TRICK (PROPERLY AND IT DIDN’T WORK)
    HELP ME

  • jp

    so i now have the same problem as all you’s but i have noticed my bios security dissapear during weird and strange installs me and me friends have performed while intoxicated on the beautifull herbal green. so i am now gona figure out what can be done…… :’ )

  • jp

    so i now have the same problem as all you’s but i have noticed my bios security dissapear during weird and strange installs me and me friends have performed while intoxicated on the beautifull herbal green. so i am now gona figure out what can be done…… :’ )