Dull screen my pc is fully charged and on high performance but my screen is dull as if it was on power save. It is exactly the same when plugged in help Cheers G.

This recalibrate's the battery.

Charge the battery completely. Monitor the battery indicator, which is usually found that the bottom of your computer screen, to check if the battery is already fully charged.

Plug off the power adapter and use the laptop until the battery is completely drained. To drain the battery faster, run several programs at once and keep the contrast of your screen to its highest levels. Turn off all power-saving features as well. Turn off sleep mode.

Make sure that the battery is totally drained by waiting for your laptop to shut off or go into sleep mode automatically because of very low battery charge.

Plug the power adapter again and charge the battery again completely. Once this is done, restore the power-saving features and adjust the contract settings of your screen to normal.

you can change that in power settings right click on the battery bottom right of the screen hit change power settings u will get options u want to change power settings look at the options you want to make it stay brite all the time right now you have it set to be brite only when plug is in change the option when its unplugged to brite also

Windows provides the following plans to help you manage your computer's power:

• Balanced. Offers full performance when you need it and saves power during periods of inactivity. This is the best power plan for most people.
  

• Power saver. Saves power by reducing system performance and screen brightness. This plan can help laptop users get the most from a single battery charge.
  

• High performance. Maximizes screen brightness and might increase the computer's performance in some circumstances. This plan uses a lot more energy and will reduce the amount of time that a laptop battery lasts between charges.
  Note

  • High performance doesn't appear on the battery meter by default. To turn on High performance, open Power Options by clicking the Start button , and then clicking Control Panel. In the search box, type power options, and then click Power Options. Under Select a power plan, click Show additional plans, and then click High performance.
    

If these plans don't suit your needs, you can create your own power plan, using one of these plans as a starting point.

Tips for getting more from a notebook battery.
1. Turn off Wi-Fi and BlueTooth - Most laptops have shortcut keys to instantly disable wireless networking.

2. Don't play computer games, music or DVD movies - Multimedia activities drain laptop batteries.

3. Disconnect all external device like PC Card modems, Firewire, USB devices and optical drives. Use the notebook touchpad instead of an external mouse.

4. Adjust your screen brightness - Dimming your display saves battery power. 

5. Tweak Windows Power Options - Choose a Laptop power scheme that turns off the notebook monitor and hard disk after 10 minutes of inactivity.

6. Decrease or mute the Laptop Speaker Volume.

7. Turn off all scheduled tasks.

8. Turn off Auto-save features in Microsoft Office and other applications.

9. If your PC has a built-in wireless card, turn it off or disable it when not in use.

10. Programs that are run from a CD or DVD can be copied to and run from the hard drive, which typically consumes less power than an optical drive.

Looking for the longest battery life laptop ? Actually, many factors affect the amount of time that a laptop battery can deliver power before it must be recharged. 

How to extend laptop battery life? Here are some more tips to improve your notebook's battery life:

1. If you do not use your laptop for extended periods of time (a week or more), remove the battery pack from the laptop. 

2. Do not expose the battery to high heat or freezing temperatures. Do not leave your battery in your car in the summer. Hot batteries discharge very quickly, and cold ones can't create as much power.

3. Make sure to plug your laptop charger adapter into a UPS and not directly into a power outlet or surge protector.

4. If you have a nickel-metal hydride battery, completely drain and recharge the battery once a month to maximize its capacity to hold a charge.

5. Fully charge new battery packs before use. New pack needs to be fully charged and discharged (cycled) a few times before it can condition to full capacity.

6. For laptops that work as Desktop Replacement, the battery should be re-installed every 3-4 weeks and allowed to fully discharge.

7. Leaving a battery in a laptop while using an electrical outlet for long periods of time will keep the battery in a constant state of charging up and that will reduce the life cycle of the battery.

Battery-saving sleep modes: Should I use Stand By or Hibernate

Standby mode
Use standby to save power when you will be away from the computer for a short time while working - your monitor and hard disks turn off, all applications and open files are stored in RAM. When you want to use the computer again, it comes out of standby quickly, and your desktop is restored exactly as you left it. 

Hibernation Mode
Use hibernation to save power when you will be away from the computer for an extended time while working - your computer shuts down to save power but first saves everything in memory on your hard disk. When you restart the computer, your desktop is restored exactly as you left it. 

When you choose Start, Turn Off Computer in Windows XP, your options are Stand By, Turn Off, and Restart. To Hibernate, place the cursor over Stand By, then hold down Shift and click.

New batteries are shipped partially charged. Before you start using your device, it is recommended that you charge the battery. Some batteries perform best after several full charge/discharge cycles. You can charge the battery in two ways: • Charging the device’s battery by connecting the power adapter. • Connecting your device to a PC via the provided Mini USB cable. Note: Only the AC adapter and USB cable provided with your device should be used to charge the device. Charging is indicated by a solid amber light on the left LED indicator. As the battery is being charged while the device’s power is on, a charging icon will be shown on the title bar of the Today screen. After the battery has been fully charged, the left LED becomes green and a full battery icon appears on the Today screen’s title bar. Warning! Do not remove the battery from the device while you are charging it using the AC or car adapter. As a safety precaution, the battery stops charging when it overheats. When the low-battery warning appears, do the following: • Immediately save your current data. • Synchronize with your PC or connect the power adapter to charge the battery. • Turn off your device.
Hope this helps, let me know if I can help you with anything else.
JimmyC

Solution? - not sure yet but having read solution by Hector_ahab, tried various F() buttons in conjunction with Fn button. Pressing Fn with F6 switches between black and normal screen on my Acer Aspire 5920. Fingers crossed!

3 ways to solve it:

1.) Take out and put battery back in.

2.) Plug into a wall or car charger but not a PC USB charger. This does not work with PC USB connection for some reason.

3.) Hold red on/off button to force a reset.

4.) The big battery icon should appear on screen.

5.) Let charge until mostly or fully charged.

7.) Turn on phone. It should boot.

2 - Hard Reset

To perform the hard reset, hold down the center select button in the middle of the D-pad/joypad (the raised silver one.) Then, continuing to hold it for at least five seconds, press the power button to allow the device to power up. Continue to hold the select button until you get a screen which asks if you want to perform the master reset. Let go of the select button, and press the appropriate soft action key to respond yes.
REMEMBER! A hard reset erases ALL of your data!!! This is why the Backup is so important.

You could get Sprite Backup. In addition, install it to your Storage Card and save your backups there as well. That way you can restore on the road without a PC.

3 - Update your phone's firmware

check on the keyboard, lots of the keys have an extra function, normally written in blue.

Look for the two that show brightness... it the same symbol on TVs that sets brightness...

now look for the "FN" key.

press and hold the "FN" key and then press the brightness + key... this should make the display brighter...

well...dull screens are usually due to either low power or a bad video card..check the power supply to be sure its charging the battery

ya there is a option in your laptop in power option 1 is performance please active this option .then u never face this type of problem