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IF you forget your BIOS password


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You can't enter into CMOS setup, if you have forgot the password. There is no way to find the password again. But, you can remove the BIOS password using some utilities or some other ways.



Removing CMOS battery or changing the CMOS jumber settings. If you are having the older type mother board, it is enough to remove the CMOS battery from the motherboard and insert it again after some time. In case of the new mother boards, the battery charge will

persist for 3 to four days. So, it is good to change the jumber settings near the CMOS battery. For finding the CMOS jumber, refer motherboard manual.



You can use the password crackers.

You can get the BIOS password crackers from the following links.



Use any one of these tools. The current settings will be turned to default settings.



With the C Program.

# include <stdio.h>

# include <dos.h>

typedef unsigned char byte



byte i;

for (i=0;i<=225;i++)






This should be excecuted in DOS prompt. This will remove the password.



If you use any one of these three ways, and boot the system, you will get an error message. "CMOS checksum error. Press F2 to continue". Press the key, and select 'Load default settings'. Make necessary changes in

settings and exit with save.


Back door passwords for BIOS are also available. They are different for different BIOS, based on the manufacturers and versions.





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0x71 is a hexadecimal value.

The first call to outp(); calls it with a "o" (lower case letter o) but it should probably be a 0 (zero).

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#include <stdio.h>#include <dos.h>typedef unsigned char byteint main() {  byte i; for(i=0; i<=225; i++) {    outp(0x70, i);    outp(0x71, i);  } puts("Done."); return 0;}


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  • 3 weeks later...

I will be the first to admit that I have not read the Jed Clampett Definitive Guide to Home Computer Repair, however, there are a few things here that I must disagree with.


The first method of using the CMOS jumper to reset is tried and true.


However, using a password cracker or even the C script would pre-suppose that you had access into either Windows or at the very least DOS. IF you can't get past a BIOS password, how do you get to DOS? Even using a boot floppy you still have to get past the BIOS.

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