I recently upgraded my MacBook Pro to Yosemite. Everything was fine ... then suddenly the MacBook Pro does not start up. It boots with some distorted graphics, and then just immediately restarts.
I tried Recovery by pressing shift key. Command + Shift. Nothing. Same thing...Apple logo..progress bar, grey screen, fan speeds up ... shutdown.
I tried Apple's recommendations. But surprisingly same sequence..
- Option-Command-P-R -- It did give me sound twice and above sequence repeats. (I don't see those icon etc for hardware test..why ?)
- Pressed shift, same sequence repeats.
- Command V Video here ... no error but same sequence ... it shows grey screen and restarts.