CMOS chip
and battery
The Phoenix BIOS (Basic Input/Output System) is a simple program that resides on the CMOS ROM (Read Only Memory) chip on a computer system's motherboard. There are a couple of major BIOS manufacturers, including Phoenix. Each BIOS contains a set of initial parameters that can be set using a simple text interface. A security feature is built into the program that allows the computer user to set a password for the BIOS. When activated, the computer will not complete the booting up process until the password is entered. If the password is unknown, then it must be reset in order to gain access to the computer.
Instructions
1. Turn off the computer and unplug all cables from the back of the case, labeling each one if it isn't color coded. This must include the power cable, which should also be unplugged from the wall or power strip.
2. Open the computer case by removing the screws on the back that hold the side panel on the frame. Some systems will use thumb screws and no tools will be required. However, most computer systems will require the use of a Phillips head screwdriver.
3. Locate the CMOS battery. It will be located near the CMOS chip and looks like a large watch battery (see the picture above). Check to see if there is a three-pin jumper switch near the CMOS battery as well. It is only present on some motherboards and will be used in step 4 if it is there.
4. Remove the CMOS battery. Leave the battery out for 30 minutes to allow any residual electricity in the CMOS ROM to discharge. This will effectively reset all settings in the CMOS to default values and clear the password.
If the three-pin jumper is present, leave the CMOS battery in place. Move the jumper on the pins from the side it is on to the opposite pins. Then attach the power cord and reboot the system. It will not boot up but actually clear the CMOS settings. Remove the power cord and move the jumper back to its original pins.
5. Re-attach the computer system cover and replace the screws holding it in place.
6. Re-attach all of the cables to the back of the computer and reboot. Your Phoenix BIOS password is now reset and you will be able to boot into your operating system. You may need to re-enter the CMOS settings if it doesn't recognize all of your components such as expanded memory or DVD drives, etc.
Tags: CMOS battery, CMOS chip, CMOS settings, computer system, near CMOS, Phoenix BIOS