Hi,
The battery may be worn and need to be replaced, the battey contacts could need to be cleaned (if they can be), or there could be other hardware or software issues. Check with a real computer shop (one that does its own in-house servicing) or Acer's Support.
Acer - USA - Service and Support - Drivers
http://us.acer.com/ac/en/US/content/support
Acer - Worldwide
http://www.acer.com/worldwide/selection.html
References to Vista also apply to Windows 7.
Check with System maker's Support, their on-line documentation and drivers, and their forums (if any) for known issues. Some maker's have issued BIOS and other updates to help with battery problems.
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Do these to clear corruption and repair/replace damaged/missing system files.
Run DiskCleanup - Start - All Programs - Accessories - System Tools - Disk Cleanup
Start - type in Search box - COMMAND find at top of list - RIGHT CLICK - RUN AS ADMIN
sfc /scannow
How to Repair Windows 7 System Files with System File Checker
http://www.sevenforums.com/tutorials/1538-sfc-scannow-command-system-file-checker.html
Then run checkdisk (chkdsk).
How to Run Disk Check in Windows 7
http://www.sevenforums.com/tutorials/433-disk-check.html
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Other information that might help :
Control Panel - Power Options - Power Plans - Change plan Settings - check the Advanced Settings for drain and usage settings (this is how much to be used and not how much or how long to charge). Actually what causes a lot of wear on a battery is draining it
too low repeatedly. With today's systems over-charging is not an issue.
Here are some tips to help and troubleshoot battery related issues.
Old battery? Unplug power to computer - remove battery and clean the contacts with a pencil eraser (do not use this if your battery has thin slots - just clean the knife edges that fit into them and be careful). Batteries do wear out if old, or it could
be a problem with the computer.
Check with the support of the system maker and many of them have on-line forums.
Newer type Litium-Ion batteries usually last longer if you do not discharge them below 30% however on a laptop that will not extend their life that much. Best is to use A/C adapter whenever possible.
I use the free version of BatteryBar to monitor my battery. Click the Green button on the Yellow box on right side of page to download latest stable version.
BatteryBar - Free version available
http://osirisdevelopment.com/BatteryBar/index.html
Another good program
Vista Battery Saver - Free
http://www.codeplex.com/vistabattery
Problems with power usage and battery life - Mr Fixit
http://support.microsoft.com/gp/windows\_battery\_power\_settings
You might also want to check with the System Maker and any forums as many use their own proprietary software to monitor the battery and their could be known issues with your battery.
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Taking care of your laptop's battery
http://windows.microsoft.com/en-US/windows7/Taking-care-of-your-laptop-battery
Battery meter: frequently asked questions
http://windows.microsoft.com/en-US/windows7/Battery-meter-frequently-asked-questions
Conserving battery power
http://windows.microsoft.com/en-us/windows7/Conserving-battery-power
Solutions to common battery problems
http://windows.microsoft.com/en-US/windows7/Solutions-to-common-battery-problems
How accurate is the battery meter?
http://windows.microsoft.com/en-US/windows7/How-accurate-is-the-battery-meter
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Try this - make a Restore Point
How to Create a System Restore Point in Windows 7
http://www.sevenforums.com/tutorials/697-system-restore-point-create.html
How to Do a System Restore in Windows 7
http://www.sevenforums.com/tutorials/700-system-restore.html
Then Control Panel - Device Manager - Batteries - Double Click on each item - Drivers tab - Update Drivers (which may not do anything) - then Right Click and UNINSTALL each - REBOOT which will refresh the Driver stacks.
Problems with power usage and battery life - Mr Fixit
http://support.microsoft.com/gp/windows\_battery\_power\_settings
Hope this helps.
Rob Brown - Microsoft MVP <- profile - Windows Experience : Bicycle - Mark Twain said it right.