Yosemite gray screen no startup keys working I restarted my macbook pro this morning and it started up with a chime and now is stuck on the grey screen. I have tries holding any different key combinations, none of them work, except resetting the pram, which does cause the computer to restart.

I have tried option, r, s, d, command shift v, command v, shift (before and after the chime), command option d r. 

FYI I have been running yosemitr for a while with no problems. I shut my computer last night and it was working fine. This happened when I turned it on today.
Disconnect everything from the Mac and then power it off.

Perform recovery according to these steps.


http://support.apple.com/en-us/HT4718


If that fails, then you may need support from Apple to determine the version of OS X that shipped with the Mac so you can restore that and start over/restore from a backup once the hardware is known to work. Or it needs a repair for hardware issues.