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Dell Inspiron 6400 BIOS Password Anyone? – Rajib's Blog Rajib's Blog

Dell Inspiron 6400 BIOS Password Anyone?

So this Dell Inspiron 6400 laptop lands at my doorstep. New owner reported that the erstwhile owner had forgotten the password. Since I had reliable information that this laptop was not purchased from a mugger for $20 and was inherited genuinely, I set about genuinely trying to restore the functionality of the machine.

The password on the laptop that was set, was not a Windows password. It was a BIOS password. Much harder to deal with. While there are utilities on Hiren’s Boot CD to perform simple reset of Windows passwords, the BIOS password tools do not work if the BIOS requires a password even before booting from any device. The only solution, reset the BIOS password or get rid of it.

There were textbook websites offering computer maintenance tips, some suggested battery removal, some suggested battery terminal shorting, some suggested shorting the pins of a particular chip on the motherboard, some suggested contacting Dell. 

Searching Google revealed a surprise: there were tons of websites, each offering a BIOS password back-door for amounts between $20 – $50. Pay the money, email the BIOS Error Codes and voila! You get the BIOS back-door password by email. Simple. Not. Most of these websites are run by people with better financial acumen than technical. They just ride the google keywords boat and $20 is not what I was willing to spend on this free exercise.

Delving deeper, I wanted to download the same tools that these 1-page websites were using. Surely there are enough well-meaning people in the world who would rather help people than leech off their misery.

A little under an hour later, I stumbled on the motherload – Dogbert’s Blog.

Dogbert has been researching and reverse engineering locked up devices for a while now and provides comprehensive education and tools at no cost to those who manage to sift through the filth in google search results.

Among the many tools on the website, there was one for generating passwords for Dell machines whose BIOS ID ended with 595B. Lucky strike for me.

Downloaded the tool, ran it three times (my bad) and got the back-door password. BIOS unlocked. I went a step further and taped the BIOS backdoor password to the bottom of the laptop; should the laptop ever lock itself up automatically again – as some users reported.

Windows XP starts up and I am greeted with Windows Password required screen. By now, my paying client’s work had been on the bench long enough and I needed to earn my $20. Hence laptop was returned to owner with advise to contact erstwhile owners about the Windows password.

If it comes back to me, you will know. Because there will be yet another article about password removal. And the article will be laced moderately with google ads. You see, I too ride the google keywords boat.

Here’s a tip for the paranoid: If you are sensitive about your data, use TrueCrypt to protect it and don’t bother with setting BIOS / Windows passwords.

Update: Now that the TrueCrypt project has gone belly-up, a number of other alternatives have sprung up. Some free, some paid. Check out this article to discover a few alternatives >>


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11 Responses

  1. joel says:

    I followed up on it but i dont know how to do it can u guild me through ;/

    • Rajib Ghosh says:

      Hi Joel,

      You need to type in the BIOS code exactly as shown. Capitals and all.
      If you type correctly, the unlocking password will be displayed on the computer screen and you can type that into the laptop to unlock it.


  2. joel says:

    Yea but i have not reach there yet , i have downloaded the thing that was told to download but for some reason its doesn’t work on the computer so as it was said to download python but i really do not know how to operate python. i am not sure if you can help me but i would appreciate it dearly. Even if you can do it for me . thank you for time .

    • Rajib Ghosh says:

      Dear Joel,

      The program was written in the Python language and you need to install Python Runtime for Windows to run it.
      Hopefully you will be able to figure out how to install Python and run the program. If not, use the ‘Contact Form’ (not in comments) and let me know the:
      – Make, Model, Serial of your laptop
      – The BIOS code that is being display (type capitals as capitals, lowercase as lowercase. spaces, dashes matter – so type it accurately.)


  3. karim says:

    DELL inspiron 6400 this is my laptop, i ill put it password before 4 years on the BIOS now i forgot password ,already remove bios battery 4 days motherboard without battery ,but not remove the password,now how torecover the password please help me,,,,SERVICE TAG–6T5P53J,

    • Rajib Ghosh says:

      Dear Karim,

      The password of the Dell 6400 is stored in NVRAM. You cannot remove it by removing the battery alone, it needs a motherboard soldering job.
      Alternatively, you can try the utility that is mentioned in the blog article. Its a free software and if you give it the BIOS code, it will tell you the backdoor password to remove the existing password.


  4. Mushtaq says:

    gr8…….very help full. saved me 30 £. thanks alot

  5. naseef says:

    i have a prob my dell laptop insp6400 blocked in bios password how can reset .i am technician

  6. Jack says:


    I have a Dell Inspiron 6400, BIOS locked

    Service tag is gz2g2c1-595b

    I would really appreciate if you can provide me the password.


  7. prasad says:

    I have dell inspiron 6400 bios locked
    service tag is 3hy602j-595b
    i would really appreciate if you can provide me the password

  8. prasad says:

    I have dell inspiron 6400 bios locked
    service tag is 3hy602j-595b
    i would really appreciate if you can provide me the password

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