My mac has been working perfectly for the past 3 years. I opened it up after waking up and nothing happens, the screen is illuminated (I can see the apple logo on the back glowing) but is unresponsive. I tried resetting it and doing a pram reset but nothing will work. When I plugged in an external display I was able to boot it into safe mode and got to my desktop. Connected to the monitor the Mac will not boot unless in safe mode? Any ideas? I am a university student and rely on my computer for everything. Thanks in advance!