Why won’t my MacBook start?

If your charging cable is MagSafe, is you connect the charger, is the LED on the cable green or orange?

If the battery is completely dead, it won't start, and if you see no LED at all, the charger may have failed leaving you with an (unknowingly now dead) battery.

try it anyway , don't worry about the screen color.

There is a limited amount you can do if the mac is unresponsive—your next step is take it in:

In or out of warranty you can get a free over the counter 'Apple Service Diagnostics' test

Genius reservation http://www.apple.com/retail/geniusbar/

on-line https://getsupport.apple.com/

check warranty https://checkcoverage.apple.com/

resetting NVRAM/PRAM http://support.apple.com/kb/ht1379

You can try this—

1. Shut down the computer.

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.

3. Turn on the computer.

4. Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.

5. Hold the keys down until the computer restarts and you hear the startup sound for the second time.

6. Release the keys.