Summary of various methods for clearing BIOS passwords

Summary of various methods for clearing BIOS passwords

We know that there are two types of BIOS passwords: User Password and system password. The former is used only when BIOS is set, and the latter is required before self-check. To ensure computer security, set the BIOS password for the computer. Over time, many friends may easily forget the Bios password. How can I clear the BIOS password? The following small series will introduce several cleanup methods for you. Let's take a look!

Method/step

1. There are also many cases to clear the BIOS password. If you can enter the operating system, you can try to clear it by using the command. Start → run → Enter CMD and click OK (or press Enter) to open the Command Prompt window.

Program. For more information, see related experience.

3. Input in sequence (the _ symbol is the default and does not need to be entered. Note the differences between o and 0, and the use of spaces and enter keys ):
_ O 70 16
_ O 71 16
_ Q

4. Because the BIOS version is different, you can use different commands to crack the password:
-O 70 10
-O 71 ff
-Q

5. Software operation method:
There are many software that can be viewed, cleaned, and modified in the graphical interface of the operating system BIOS password.

6. You can also use the Cmospwd software to view the BIOS password in the Command Prompt window. It supports various BIOS, including Acer, AMI, AWARD, COMPAQ, DELL, IBM, packard bell, PHOENIX, and zenith ami, the operation method is: start the program under DOS, and the BIOS password will be displayed.

7. If you cannot enter the operating system, you only need to use a snap-on battery. After the computer is shut down, the button battery on the motherboard will continue timing. if you remove the button battery (dozens of seconds ), the motherboard information will be cleared due to power failure, so as to clear the user's own password, restore to the BIOS factory default value (no password), and then press it.

8. Of course, the timing battery of some mainboards cannot be switched out (the wires are welded to the battery). In this case, the power can be switched off and the Jumper can be switched (two or three short circuits) reset (because the version is different, you can follow the instructions ).
Tip: some high-end business computers cannot use common methods to crack the BIOS password (Protection Information), so be cautious when setting the password.

9. The most common and simplest method-Debug Method

In general, the computer's CMOS settings can be accessed and changed through the 70H and 71H ports. The simplest way is to clear all the ports, that is, to change them to the default settings. The following program section is to use the Debug Command to clear the CMOS Data, Debug is an external DOS Command, you can find it in the Windows \ Command directory, start the computer to the MS-DOS environment, enter Debug in the DOS symbol and press Enter. # The process is as follows:
C: \ dos & gt; debug
-O 70 21
-O 71 20
-Q
Or:
C: \ dos & gt; debug
-O 70 10
-O 70 01
-Q
Note: "-" is generated by the system itself, so you do not need to enter it.
Then restart and you will find that the user password has been cleared .. (I will use this method to overclock the PIII800 machine in the school, and add 0.5v....results ...... the teacher is at a loss ....)

10. The most straightforward method-discharge method (the most practical method of BC ...)

In this way, you need to open the chassis, find the CMOS battery, and discharge it. In fact, most of the current mainboards are configured with jumpers or DIP switches for CMOS battery discharge. Generally, find the jumper or switch, and switch for several seconds or switch for several seconds. If your motherboard is an old motherboard, there is no CMOS battery discharge jumper or DIP switch, or you cannot find the motherboard manual, you do not know which group is a CMOS battery discharge jumper, then you just need to unplug the CMOS battery and connect the exposed pins to one sub-device (in fact, it will take a few seconds, but some articles say it will take one hour .... khan ..... that is, let CMOS automatically clear the content without power supply for a long time.