PLEASE help me. MacBook won't turn on.

Be absolutely certain you are using an authentic Apple power adapter.

Troubleshooting: My computer won't turn on

After all the obvious causes you are directed to perform anSMC reset. Read and follow all these steps:

Before Resetting the SMC

Try each of the following steps in this order before you reset the SMC. Test the issue after completing each troubleshooting step to determine if the issue still occurs.

1. Press Command + Option + Escape to force quit any application that is not responding.
2. Put your Mac to sleep by choosing the Apple () menu from the upper-left menu bar and then choosing Sleep. Wake the computer after it has gone to sleep.
3. Restart your Mac by choosing the Apple () menu from the upper-left menu bar and then choosing Restart.
4. Shut down your Mac by choosing the Apple () menu from the upper-left menu bar and then choosing Shut Down.

Resetting the SMC on Mac portables with a battery you can remove

1. Shut down the computer.
2. Disconnect the MagSafe power adapter from the computer, if it's connected.
3. Remove the battery (to remove the battery - click here: MacBook or MacBook Pro).
4. Press and hold the power button for 5 seconds.
5. Release the power button.
6. Reconnect the battery and MagSafe power adapter.
7. Press the power button to turn on the computer.

Still having problems? Replace steps 6 and 7 with the following:

1. Reconnect MagSafe power adapter.
2. Press the power button to turn on the computer,
3. Then reconnect the battery.

Resetting the SMC on portables with a battery you should not remove on your own

1. Shut down the computer.
2. Plug in the MagSafe power adapter to a power source, connecting it to the Mac if it's not already connected.
3. On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
4. Release all the keys and the power button at the same time.
5. Press the power button to turn on the computer.

If you have no success with the above try troubleshooting your MagSafe adapter:

Troubleshooting MagSafe adapters

If all else fails schedule an appointment for the Genius Bar. Diagnosis and recommendations are free.

Try steps 3, 4, and 5 from the last procedure. Listen for any sounds of activity. Repeat those steps. Repeat them with and without the power adapter connected.

Press the Caps Lock key. Does it illuminate, ever?

If it refuses to power up, there is little else you can do about this other than to have Apple repair it. A defective power adapter, though unlikely from what you described, might be a cause that would be inexpensive to fix. Borrow one from a friend. If it fits the Mac it is OK to use for troubleshooting purposes.

If you are concerned about the information on its hard disk that is now inaccessible, it is very likely that it is still perfectly intact. Extracting it would require disassembly and installation in an enclosure. They are inexpensive, but the labor ought to be performed by someone familiar with Macs.