Remove and install the cmos battery on a acer aspire 9401z laptop

Perhaps, you meant to say that you have an Acer Aspire 9401Z.

Press F2 (during POST) to enter the BIOS utility. Or if you want to clear the cmos, just remove the removable coin shaped battery for some ten minutes to do the same effect as "clear cmos jumper".

All laptops have a CMOS, or "Complementary Metal Oxide Semiconductor," battery.
The main purpose for the CMOS battery is to keep the system time, date and BIOS settings even if the computer is turned off or the main battery dies.
Individual Acer Aspire laptop models differ somewhat, but the general steps are the same when replacing a dead CMOS battery.Preparation

Read through the owner's manual for your particular Acer Aspire laptop to determine what kind of CMOS battery you need.
Purchase the battery through Acer or a local or online computer parts dealer.
Turn the laptop off and unplug it.
Also unplug any external hard drives, cameras or other external devices.
Turn the laptop over (bottom facing up), then touch something metal to remove static charge.
Removal
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.
Installation
Plug the new CMOS battery cable into the motherboard.
Slide the battery partially under the laptop casing to hold it in place, then align the cover with the slots on the bottom of the laptop housing.
Replace the screws, then turn the laptop back over.
Settings
Plug the laptop in and turn it on.
Enter your BIOS (usually by pressing "F1," "F2," F10" or the "Delete" key) before the operating system loads.
Follow the BIOS prompts or refer to your Acer Aspire owner's manual to reset your time, date and desired system settings.
BIOS Reset
Any time the CMOS battery is unplugged for more than a few seconds, your BIOS will be reset to the default manufacturer settings.
If you make any changes to the BIOS that cause problems with your Acer Aspire, unplug the CMOS battery for 3-5 seconds to correct the problem.
http://support.acer.com/us/en/default.aspx


Acer aspire laptop battery replacement
http://www.youtube.com/watch?v=mQTZ1AUR0uw

Remove the main battery and CMOS battery, wait for 20 min and replace back the batteries. The CMOS will then be rest to default.

Remove the main and CMOS battery, wait for 20min and your CMOS will be reset to default.

pull out the cmos battery as well as the battery, and leave it for 3 minutes. then put the reg. battery back in and boot it up. it should say password disabled. Turn it off and put the cmos battery back in, it should work now. leave positive feedback!

Before you start

1) Read through the owner's manual for your particular Acer Aspire laptop to determine what kind of CMOS battery you need.

2) Purchase the battery through Acer or a local or online computer parts dealer.

3) Turn the laptop off and unplug it. Also unplug any external hard drives, cameras, or other external devices.

4) Turn the laptop over (bottom facing up), then touch something metal to remove static charge.

Removal of the 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.

The battery should look something like this

Plugging the new battery in
Plug the new CMOS battery cable into the motherboard. Slide the battery partially under the laptop casing (somewhere to hold it in place), then align the cover with the slots on the bottom of the laptop housing. Replace the screws then turn the laptop back over.

Finalizing
1) Turn the laptop on.
2)Enter your BIOS (usually by pressing the "Delete" key) before the operating system loads.
3) Follow the BIOS prompts or refer to your Acer Aspire owner's manual to reset your time, date and desired system settings.

Reason: Anytime the CMOS battery is unplugged for more than a few seconds your BIOS will be reset to the default manufacturer settings. If you make any changes to the BIOS that cause problems with your Acer Aspire, unplug the CMOS battery for 3 to 5 seconds to correct the problem.

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yes laptop`s has a cmos battery but can not be removed . most laptops battery are sealed
check this link http://www.laptopparts101.com/cmos-rtc-battery/

Bottom of the laptop, the big cover that comes off. Below the wlan card