Why does my mac keep crashing?

Steps to verify or repair Kernel Panic (KP):

Boot into safe mode (restart holding down SHIFT key).

• If no KP, then some 3rd-party thing is causing the problem.

• If yes KP, then most likely hardware related.

  • Run the Apple Hardware Test suite, extended tests at least twice

Using Apple Hardware Test on computers with OS X 10.7 or later Mac NoteBook and Desktop computers shipping with OS X 10.7 or later have a partition on the hard drive or flash storage that contains AHT. To start AHT on these computers please follow these instructions:

• Press the power button to turn on your computer.

• Press and hold the D key before the gray startup screen appears.

It takes a minute or so for AHT to start up and inspect your hardware configuration. While this is taking place, an icon appears on the screen:

When the process is complete, select your language and click the right arrow. If you aren't using a mouse, you can use the up and down arrows to select a language and then press the Return key.

The AHT console appears. You can choose which sort of test or tests to perform:

• To perform all of the basic tests, click the Test button or press the "T" key or the Return key.

• To perform a more thorough diagnostic test, select the "Perform extended testing" checkbox under the Test button before you click the Test button.

  Note: Your test results will appear in the window in the bottom-right of the console. To exit AHT, click Restart or Shut Down at the bottom of the window.