Removing laptop cover to access cmos battery

Remove the Phillips screws that secure the motherboard cover (refer to your owner's manual if necessary), then release the cover from the clips on the bottom of the plastic casing.
Lay the cover aside, then locate the CMOS battery cable on the right side of the motherboard. Unplug the cable, then remove the battery.
http://www.youtube.com/watch?v=cg_wvp1YdSI
laptop cmos battery
Acer aspire laptop battery replacement
http://www.youtube.com/watch?v=mQTZ1AUR0uw

Resetting the CMOS password on an Acer Aspire laptop is much more difficult than resetting the password on a desktop.
Disassembly steps vary from model to model, but on most models, you'll have to take apart the computer to access the CMOS battery.
Don't take apart the notebook if you don't have experience disassembling PCs.
After turning off the computer and disconnecting the AC adapter, take out the battery (different from the CMOS battery).
All visible screws must then be removed from the bottom of the notebook.
Remove all components stored to their separate compartments on the base of the notebook.
Turn over and open the PC. Lift up the switch cover and remove the screws securing the keyboard to the PC, if any are visible.
Remove the keyboard.
Remove the screws securing the monitor to the hinges, and then set the monitor aside.
Disconnect all visible cables connected to the motherboard; and then remove the screws from the top cover.
Remove the top cover to reveal the motherboard. Locate and then remove the CMOS battery. Leave it out of the notebook for 24 hours; then reinstall it and reassemble the Acer Aspire.
Other Options
If removing the CMOS battery fails to clear the password, or if you dont feel comfortable with the idea of opening your computer, you might be able to gain access to the computer using a backdoor password.
These special passwords were implemented to allow technicians to access locked computers. Not all models recognize backdoor passwords.
Most Acer Aspires use the Phoenix BIOS, and backdoor passwords for this BIOS include BIOS, CMOS, phoenix and PHOENIX.
All of these passwords are case-sensitive.

Is it an aspire ?
Resetting the CMOS password on an Acer Aspire laptop is much more difficult than resetting the password on a desktop.
Disassembly steps vary from model to model, but on most models, you'll have to take apart the computer to access the CMOS battery.
Don't take apart the notebook if you don't have experience disassembling PCs.
After turning off the computer and disconnecting the AC adapter, take out the battery (different from the CMOS battery).
All visible screws must then be removed from the bottom of the notebook.
Remove all components stored to their separate compartments on the base of the notebook.
Turn over and open the PC. Lift up the switch cover and remove the screws securing the keyboard to the PC, if any are visible.
Remove the keyboard.
Remove the screws securing the monitor to the hinges, and then set the monitor aside.
Disconnect all visible cables connected to the motherboard; and then remove the screws from the top cover.
Remove the top cover to reveal the motherboard. Locate and then remove the CMOS battery. Leave it out of the notebook for 24 hours; then reinstall it and reassemble the Acer Aspire.
Other Options
If removing the CMOS battery fails to clear the password, or if you dont feel comfortable with the idea of opening your computer, you might be able to gain access to the computer using a backdoor password.
These special passwords were implemented to allow technicians to access locked computers. Not all models recognize backdoor passwords.
Most Acer Aspires use the Phoenix BIOS, and backdoor passwords for this BIOS include BIOS, CMOS, phoenix and PHOENIX.
All of these passwords are case-sensitive.

Step 1:
The Acer Aspire stores the password in a component called the complementary metal-oxide semiconductor. This component is integrated into a random access memory chip embedded on the motherboard. The CMOS holds data that the basic input/output system - a critical software utility that controls how the computer operates at startup - accesses when the computer boots. If the BIOS detects that a password is registered in the CMOS, it will prevent the computer from booting until the user enters the password correctly. Depending on which model of Acer Aspire you own, you may be able to clear the CMOS manually. Contact Acer before attempting to clear the CMOS, as opening the computer without permission could void your warranty. Desktop Models Some Acer Aspire desktop models come with a jumper that is used to clear the password and other settings stored on the CMOS. This jumper is located on the motherboard and is often found next to a label such as "JBIOS1" or "CLR_CMOS." To clear the CMOS using the jumpers, turn off the computer, disconnect the power cable and remove the case cover. Remove the jumper shunt from pin 1 and pin 2; then place the shunt on pin 2 and pin 3. Return the shunt to its initial position after 10 to 15 seconds. If the Aspire doesn't come with a jumper to reset the CMOS, the CMOS can be reset by removing the lithium coin-cell battery instead. Removal is accomplished by pushing down on the tab securing the battery to the motherboard and lifting the battery out of its slot. Leave the battery out for 24 hours, and then return it to its original position with the positive sign facing up. Laptop Models b> Resetting the CMOS password on an Acer Aspire laptop is much more difficult than resetting the password on a desktop. Disassembly steps vary from model to model, but on most models, you'll have to take apart the computer to access the CMOS battery. Don't take apart the notebook if you don't have experience disassembling PCs. After turning off the computer and disconnecting the AC adapter, take out the battery (different from the CMOS battery). All visible screws must then be removed from the bottom of the notebook. Remove all components stored to their separate compartments on the base of the notebook. Turn over and open the PC. Lift up the switch cover and remove the screws securing the keyboard to the PC, if any are visible. Remove the keyboard. Remove the screws securing the monitor to the hinges, and then set the monitor aside. Disconnect all visible cables connected to the motherboard; and then remove the screws from the top cover. Remove the top cover to reveal the motherboard. Locate and then remove the CMOS battery. Leave it out of the notebook for 24 hours; then reinstall it and reassemble the Acer Aspire. Other Options b> If removing the CMOS battery fails to clear the password, or if you don't feel comfortable with the idea of opening your computer, you might be able to gain access to the computer using a backdoor password. These special passwords were implemented to allow technicians to access locked computers. Not all models recognize backdoor passwords. Most Acer Aspires use the Phoenix BIOS, and backdoor passwords for this BIOS include "BIOS," "CMOS," "phoenix" and "PHOENIX." All of these passwords are case-sensitive.

Shut down your laptop and disconnect all power sources. Turn the laptop over and lay it face down.

Remove the screws that secure the hard drive cover and remove the cover. Take out the remaining screws that secure the hard drive to remove it.

Locate the RAM (random access memory) and wireless card cover. This is often located in the center of the laptop. Remove the retaining screws and take off the cover.

Remove the RAM module by spreading the retaining latches on each side. Tilt the RAM module at an angle and slide it out of its compartment.

Disconnect the cables from the wireless card and remove the screws that secure the wireless card to the motherboard. Remove the wireless card from the laptop.

Locate the CMOS battery. It is about the size of a coin and is secured by a clip. Unclip the CMOS battery and remove it from its compartment. Insert the new one and reassemble the laptop.

Here's a link to a video that shows you how to do it too. http://www.ehow.com/video_4984398_change-laptop-battery.html Hope this helps! Don't forget to rate.

I have found that BIOS/CMOS Password Recovery Tool is the most effective.:
BIOS/CMOS Password Recovery Tool is a program that works instantly to remove any lost or forgotten BIOS/CMOS password. Simply boot your PC to DOS and execute the program, and get access to forgotten BIOS/CMOS passwords in just seconds
BIOS/CMOS Password Recovery Tool Service: http://www.biospasswordrecovery.com/

Hi,

If you have loast the password, to reset the BIOS password you need to remove temporarily the CMOS battery , so to reset BIOS settings.

Some model may be using NV Ram, in that case removing the battery is not enough.

The battery is located on the lower side on the motherboard.

On many DELL models the battery can be accessed from the side of DVD slot, battery slot, or RAM slot, without disassemblying the laptop.

On some model you may need complete disassembly (eg. Dell Le series).

The battery looks like a couple of coin batteries wrapped in plastic.

Before disassemblying or removing covers, always unplug adapter and remove battery.

On Dell Inspiron 8500 the battery can be accessed from a side , after removing the primary battery.

I think Dell 8500 can be set to use NV Ram to store the password.
In this case the problem cannot be solved removing primary battery, then accessing and removing CMOS battery for few minutes.

If you still cannot reset you have two way out.

Disassemble completely and access the NVRAM microswitch, or contact Dell and get master password.

You can also try one of this standard Dell factory CMOS password:

ALFAROME
BIOSTAR
biostar
biosstar
CMOS
cmos
LKWPETER
lkwpeter
setup
SETUP
Syxz
Wodj
Dell

You don' t have to remove the motherboard. Remove the CMOS battery. The CMOS battery on a laptop is many times accessible from under the computer when you take the battery out. I've found them just outside of the main battery compartment up under the palm rest. Acer may be different. If you can't find it by looking up through the holes opened up by removing the access covers in the bottom of the case, you just may have to split the case to get at them. Just be careful when you do it. All cases come apart, but many require the removal of a number of screws first.
Try removing the battery for about a minute first (with the system unplugged, of course.

The CMOS batteries in a lot of laptops are sort of hidden in the palm rest. You may be able to see it if you remove the main battery and look up into the case. The last one I changed, I could see it. If not, you will have to separate the two halves of the case and then you'll find it.