Apple macbook air won't turn on

For computers with Mac OS X 10.8 or later, if you have trouble getting your display to work with the computer, access the System Preferences menu and selection the Displays option. Then, press and hold the Option key. In the bottom right corner of the Displays window, you should see a Detect Displays button. Click that button to force the Mac OS to show all the displays, including the macbook's own display.

Otherwise, try resetting the PRAM:
by holding down the Command+Option+P+R keys on your keybord when you turn it on untill you hear the startup chime.

Happy New Year!
Kerry

just turn off your Macbook. wait in seconds and turn on.

Boot it up using the osx disk.

You could be right. What to do is start it up and hold down the trakcpad button as soon as it starts up. Failing that try the F12 key or the eject key when starting it up, sometimes actually lifting the macbook up and pointing the DVD drive downwards i.e. using gravity to let the CD drop.

If the CD ejects and it isn't the problem causing the startup problems, what I would be tempted to do if the other troubleshooting solutions have not worked, if it still under warranty or if you have Applecare, contact apple and arrange to get it taken in for repair. Failing that take it to your local Apple Store and make an appointment at the genius bar, they usually are fairly good at diagnosing problems and solving them.

Try restarting your computer while holding down the X key. This may force the computer to start up using your Mac OS X system. If it does, release the X key, then open System Preferences and click Startup Disk. Make sure your Mac OS X system is selected. If you are unable to start up using the X key, restart your computer and immediately press and hold the Option key. Release the Option key when icons start to appear in the center of the screen. Select the Mac OS X system disk, then click the forward arrow to continue starting up.
If the above attempts to reselect your Mac OS X startup volume are unsuccessful, try resetting PRAM. Shut down your computer, then turn on the computer and immediately press and hold Command-Option-P-R until you hear the startup sound for the second time. Open System Preferences, click Startup Disk, and select your Mac OS X volume.
Hope this helps. If none of these options fix your problem, bring your computer to an Apple store, they are always very helpful and almost never fail to fix the problem!

Try to reset your SMC (System Management Controller) p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px Helvetica; color: #1a1a18}
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1. If computer is on, turn it off by choosing Shut Down from the Apple menu.

2. Connect power adapter to computer and to a working power source.

3. On built-in keyboard, press (left-side) Shift-Control-Option along with power button just once. Important: Use Shift-Control-Option keys on left side of keyboard.

Note: When the LED on the MagSafe connector is orange/amber, resetting the SMC will change it to green for a few seconds, indicating that SMC was correctly reset.

4. Wait 5 seconds and press power button to start computer.

If it starts without beeping errors reset the PRAM (Parameter RAM)

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1. If computer is on, turn it off by choosing Shut Down from Apple menu.

2. Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in Step

4. Note: If keyboard does not have an Option key, use Alt key instead.

3. Press power button.

4. Immediately press and hold Command-Option-P-R keys.

Important: You must press this key combination before the gray screen appears.

5. Hold down keys until computer restarts, and you hear startup chime a second time.

6. Release keys.

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may be you laptop is dead. just see this article:may be it can help you .

http://udtekbattery.wordpress.com/2010/01/21/laptops-problem/

Leave the Macbook air turned on until the battery goes dead. Then Connect to power and start it up. That should solve the problem. You problem was caused by not letting an update install in full.

Plug the power adapter in. Then hold down the startup button for 15 seconds. The light should go off and then after a few seconds. restart normally. The macbooks have a safety device that will lock up the drive if it detects sudden movements to protect the drive...
Let me know if you're back up and running. KEN

My computer used to do the same thing, I found out it was my motherboard / logic board and a hardrive combination. end cost $1500..so i bought a new Laptop. Go and get those things tested.