reset the BIOS password on a Dell Optiplex 755

From time to time, you may have the need to reset the BIOS password on a Dell Optiplex 755. You may have forgotten the password. Or perhaps the person who entered the password forgot it, moved to a different job, or died. Or even worse, maybe some obnoxious prankster decided to set a password and not tell anyone.

Fortunately, it’s easy to purge the password. It just takes some moving of a jumper on the motherboard. Here’s how:

-Shut down your computer and unplug. For reasons that ought to be obvious, rooting around inside the computer while the power is on is a really stupid idea.

-Open up the case, and making sure to ground yourself, look at the motherboard. The jumper controlling the password will be labeled PSWD, and is usually blue. Gently removed the jumper.

-Plug in the computer and power it on again. You should get a message saying “password removed”.

-Power the computer off, unplug it, and restore the jumper to its original position.

-Turn the computer back on and hit F2 to access the BIOS. The password should be gone.



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43 Responses to reset the BIOS password on a Dell Optiplex 755

  1. Chris says:


    I am normally common with the battery and pin 1-2 to 2-3 then to 1-2

  2. Matt Vera says:

    you rock thanks. I got scared, but thanks to JM I’m back in business :) you allowed me to sell my refurbed Dell.


  3. Steve says:

    Thanks for this, worked fine. The blue jumper in mine had a nice handle on it, I guess Dell realized it would be a common need.

  4. Jonathan Moeller says:


    Mine didn’t. I guess Dell came to that realization later rather than soon.

  5. jhone says:

    A. By Using the Motherboard Jumper:

    In most motherboards CMOS battery is soldered, which makes it difficult to remove the battery. In this case we use another method.

    Almost all motherboards contain a jumper that can clear all CMOS settings along with the BIOS password. The location of this jumper varies depending upon the motherboard brand. You should read your motherboard manual to check its location. If you don’t have the manual then look for the jumpers near the CMOS battery. Most of the manufacturer label the jumper as CLR, CLEAR, CLEAR CMOS, etc.

    When you find the jumper, look carefully. There will be 3 pins and the jumper will be joining the center pin to either left or right pin. What you need to do, is remove the jumper and join the center pin to the opposite pin. e.g. if the jumper joins center pin to left pin, then remove it and join center pin to right pin. Now wait for a few seconds and then again remove the jumper and join the center pin to left pin.

    Make sure to turn the PC off before opening the cabinet and resetting the jumper.

    B. By Using Software:

    I have found that BIOS/CMOS Password Recovery Tool is the most effective.:
    BIOS/CMOS Password Recovery Tool is a program that works instantly to remove any lost or forgotten BIOS/CMOS password. Simply boot your PC to DOS and execute the program, and get access to forgotten BIOS/CMOS passwords in just seconds

    BIOS/CMOS Password Recovery Tool Service:

  6. Jeff Parker says:

    You rock. Thank you so much. I bought this PC on Ebay, and seller didn’t know the pwd. This was just what I needed, and exactly as you described.

  7. Jonathan says:

    Thank you so much. that was perfect

  8. six two design says:

    Brilliant! Thank you for such clear advice.

  9. RS says:

    Thanks a lot after spending a lot of time online reading your advise is the only one that woked. thanks a lot.

  10. dude says:

    dude u rule tnx

  11. Dennsi says:

    i was jast formating my computer dell 755 its gone blank, nothing displayed on the screen but the system unit running. anyone who can help!!

  12. Mike says:

    Life safer, I looked everywhere to try to figure this out, thought it was a virus, thank you!

  13. BIOS PRO says:

    If you are having problems with bios password I recommend this site
    it has always worked for me, they have unlocked many laptop for me over the years!

  14. Lawrence says:

    I knew there was a jumper somewhere but some motherboards dont have the prongs, anyway Thanks a Bunch!!!! Your site is the Sh#t!

  15. This worked perfect, but Ashton is still not convinced

  16. Tony says:

    Thank you!.. Tip-Top help to an idiot in need !

  17. Abdul Hamid Roshanfar says:

    Thank YOU

  18. Rosa says:

    I follow your help and it work.
    My system password has been remove.
    but it shows “Hard disk #MAM9V…… is protected by a password”
    and let I enter some password.
    I don’t know what does it means. I never set harddisk password.

    please help me.
    Sorry for my poor English.

  19. Marc says:


    A hard disk password will follow the hard disk, so even if you put it into another computer you will still be required to enter the password. I don’t believe there is any way to get around this password, other than maybe contacting Dell.

  20. priyesh says:


  21. Fabio Castro says:

    Problem solved, thank you.

  22. Jim Wicks says:

    Many thanks for the info. worked a treat.
    Saved us £65, which Dell wanted to clear the password.

  23. Jonathan Moeller says:

    Seriously? 65 pounds? That’s not cool.

  24. Pete says:

    This worked on my OPTIPLEX GX620. Removing the battery did not work. Thank You Pete

  25. nr says:

    thanks mate. It was really helpfull.

  26. After a lot of research and many attempts to unlock my Dell Laptop with bios password, while talking to Dell Support, I finally found this website

  27. Benon N ike says:

    Perfect i Hav e experiment this live my self for confirmation.

  28. Anonymous says:

    Wow, you saved me. I am a student and recently bought this computer used and noticed the password on the BIOS. I didn’t think much of it because we have these same computers at our school and to clear the BIOS, we would remove the battery, plug in the computer, wait until it said the voltage was low, and then put the battery back in and boot it. I tried that and it didn’t work, so I found your article. It worked!!! Thank you so much. It was a bit hard to find at first because the person that had it before me scribbled out the PSWD label with sharpie, but I found the only blue jumper and tried it. I’ll have to tell my IT administrator about this because she’ll really be pleased!!!

  29. Susan says:

    I took out my battery thinking it would reset my administrator password that got changed without my permission either by a hacker or my a housemate, and now my computer died. It stops downloading when at the crc files. The hard drive is fine, it seems likely the motherboard is fine, but not sure, it may be the graphics card. I pulled the blue chord off, replaced it, not sure even if I got it right to end the password.

    The computer says there are no passwords, but my hard drive says it has passwords when being viewed from another computer. No viruses, so what may have I done to my computer? I want to fix it, so if anyone has any ideas please let me know. Thanks.

  30. Jonathan Moeller says:

    It sounds like your hard drive is encrypted.

  31. Mohamed says:

    it’s working, thank you.

  32. Demonax says:

    Thanks for the info!!! Very helpfull

  33. Felipe Duque says:

    Thank you so much …

  34. Adeel Samo says:

    Thanx it worked on Gx755 I was searching for this finally i solved it
    Thanx :-)

  35. Ria Kruisheer says:

    It was a success, thanks, Ria from the Netherlands

  36. Rafeeq says:

    Thank you so much , its worked on optiplex 780

  37. kgg says:


  38. Melvin Mejia says:

    Gracias pude resolver mi problema

  39. Thx a lot, it run perfectly !

  40. Duncan M says:

    Nice.. thanks.. worked well.

  41. Peter K says:

    So many experts tell you to switch jumper position. The advice you gave about booting with the jumper removed saved me quite a few grey hairs!