Why Won't My MacBook Pro Turn On?
If your MacBook Pro is not turning on or showing a picture on the display, please go through the following troubleshooting steps.
Whenever you are troubleshooting your Mac, uplug any and all devices connected to the computer - printers, external hard drives, input devices, etc. Then try to startup your computer again.
Locate the battery indicator light on your MacBook Pro (note: the MacBook Air does not have this feature). The light should appear next to a button on the bottom of your computer or on the side. Press the button and the light will indicate whether or not your battery has power.
Faulty MagSafe Adapter
To test your MagSafe power adapter, first check the electrical outlet you are using by plugging in another device such as your cell phone. If the outlet works, trying unplugging your power adapter for a minute and then plugging it back into your Mac. If the LED on the power adapter does not light up once it's plugged back in, the MagSafe might be damaged.
Checking The MagSafe Adapter
If you suspect the MagSafe adapter is the culprit, take a careful look at it for any damage or wear. Check to see if any pins are out of place on the connector if there is anything stuck in the connector. Also check the cable itself to see if it is worn or frayed - especially near the ends (this is very common). If any liquid has been spilled on the MagSafe, that could also prevent it from working.
If you are still having problems, you can attempt to reset the System Management Controller (SMC). Find instructions for resetting the SMC.
Another possible cause for startup issues could be a faulty hard disk or improperly installed RAM. Make sure any recently added hardware is properly installed and compatible with your specific Mac model. You could also try removing any non-original hardware components to see if that corrects the problem.
If you are unable to boot up your computer after going the steps listed above, you might want to consider making an appointment at the Apple Store Genius Bar or with another Authorized Apple Service Provider. Remember, even if you didn't buy your Mac from the Apple Store you can still make reservations at the Genius Bar.