Answer
This question was answered on March 29, 2007.
Much of the information contained herein may have changed since posting.
The best method to reset a BIOS password depends on what BIOS the computer has. Common BIOS's include AMI, Award, IBM and Phoenix. Numerous other BIOS's do exist, but these are the most common.
Some BIOS's allow you to require a password be entered before the system will boot. Some BIOS's allow you to require a password to be entered before the BIOS setup may be accessed.
The general categories of solutions to reset a BIOS password are:
- Using a Backdoor BIOS Password
- Resetting the BIOS Password using Software
- Resetting the BIOS Password using Hardware
Reported BIOS backdoor passwords for other manufacturers include:
Dell- Dell
Biostar- Biostar
Compaq- Compaq
Enox- xo11nE
Epox- central
Freetech- Posterie
IWill- iwill
Jetway- spooml
Packard- Bell bell9
QDI- QDI
Siemens- SKY_FOX
SOYO- SY_MB
TMC- BIGO
Toshiba- Toshiba
Resting the BIOS password using software:
Every system must store the BIOS password information somewhere. If you are able to access the machine after it has been booted successfully, you may be able to view the BIOS password. You must know the memory address where the BIOS password is stored, and the format in which the BIOS password is stored. Or, you must have a program that knows these things.
Resetting the BIOS Password using Hardware:
f you cannot access the machine after if has been powered up, it is still possible to get past the BIOS password. The BIOS password is stored in CMOS memory that is maintained while the PC is powered off by a small battery, which is attached to the motherboard. If you remove this battery, all CMOS information (including the BIOS password) will be lost. You will need to re-enter the correct CMOS setup information to use the machine. The machines owner or user will most likely be alarmed when it is discovered that the BIOS password has been deleted.
On some motherboards, the battery is soldered to the motherboard, making it difficult to remove. If this is the case, you have another alternative. Somewhere on the motherboard you should find a jumper that will clear the BIOS password. If you have the motherboard documentation, you will know where that jumper is. If not, the jumper may be labeled on the motherboard. If you are not fortunate enough for either of these to be the case, you may be able to guess which jumper is the correct jumper. This jumper is usually standing alone near the battery. If you cannot locate this jumper, you might short both of the points where the battery connects to the motherboard.
If all else fails, you may have to clear the BIOS password by resetting the RTC (Real Time Clock) IC (Integrated Circuit) on your motherboard.
Many RTC's require an external battery. If your RTC is one of this type, you can clear the BIOS password just by unsocketing for 10 minutes and then replace it.