I forgot my bios password.ihave lenovo g580 leptop.how ken start my leptop

SOURCE: Lenovo Notebook Problem

Sorry, there isn't a way to get past the password other than to contact Lenovo. Resetting the CMOS will do nothing. They will ask for proof of ownership before they do anything. I believe they have a "backdoor" password.

SOURCE: Lenovo n500 forgot bios password

Hello, If you forgot your BIOS password,do not worry, you can reset your system back without requesting a BIOS password,Simply unscrew your laptop and get the motherboard of your laptop, locate the CMOS battery on the motherboard and remove for sometime for the battery to discharge say 4-10minutes,or better still if you can locate the jumpers for the BIOS and reset it,the BIOS password will be removed.It is the battery that keeps the BIOS chip alive by suppling it power,if power is not supplied to this chip,then the information on it will be lost. So, remove the battery for some minutes or reset your BIOS jumper on the motherboard WISH YOU THE BEST.

SOURCE: i am forgot bios password

The only simple way to Erase the forgotten Bios Password is to Reset the CMOS Battery.

SOURCE: i forgot my bios supervisor

Hi,
Are you the one who set up the BIOS password? If not, unfortunately, there's no way for us to retrieved the password. The only way you can reset the password to default settings is to reseat the CMOS battery on the motherboard, its a circular thing that looks like a battery of a watch,sometimes a pin hold it, just detached it then wait for at least 30 minutes then connect it back again,
Note: Before you reseat the CMOS battery,make sure that everything is unplugged on the computer, like AC adapter,battery and all external devices...

Hope this will help...Your response is very much appreciated...

Brian Sullivan

• 27725 Answers
• Posted on Nov 28, 2012

SOURCE: bios password for Lenovo T400

Restart your computer repeatedly tapping the f8 key to enter safe mode while the screen is black once in safe mode where the only things working will be your keyboard and mouse allowing you to attempt to repair your computer

As the computer is booting repeatadly press the F8 key as the computer is booting

If done properly the user should get to a screen similar to the below screen.

Select the option for Safe mode command prompt only

Windows Advanced Options Menu
Please select an option:

Safe Mode
Safe Mode with Networking
Safe Mode with Command Prompt

Enable Boot Logging
Enable VGA mode
Last Known Good Configuration (your most recent settings that worked)
Directory Services Restore Mode (Windows domain controllers only)
Debugging Mode

Start Windows Normally
Reboot
Return to OS Choices Menu

Use the up and down arrow keys to move the highlight to your choice.

select safe mode with command prompt

Then type at the C:\> prompt: 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.

Youll notice the password is gone.

If this fails try typing

At command prompt type debug
you will get a - prompt where you can type the following (<enter> means press enter, not type enter*)

A <ENTER>
MOV AX,0 <ENTER>
MOV AX,CX <ENTER>
OUT 70,AL <ENTER>
MOV AX,0 <ENTER>
OUT 71,AL <ENTER>
INC CX <ENTER>
CMP CX,100 <ENTER>
JB 103 <ENTER>
INT 20 <ENTER>
<ENTER> just hit enter on this line
G <ENTER>
Q <ENTER>

Basic BIOS password - works 9.9 times out of ten

If this fails you will need to

Select safe mode with networking to download

you could download all of these or just one save them to a usb drive for later use if one fails to remove the password

http://www.tech-faq.com/reset-bios-password.html

At some stage you might need to press Ctrl+Enter rather than just Enter if on a Dell Latitude E5410

http://majorgeeks.com/CmosPwd_d239.html

A CMOS BIOS password recovery tool

Editors note: This tool should only be used by experienced computer users.

Please see the enclosed read me if you would like to run it from Windows.

Failure to follow instructions (from Windows) will cause your anti-virus to flag this as a virus.

Hope this helps.