Hi guys, Thanks for you help. I'll keep this factual: System: 15'' Macbook Pro. Early 2011. 2,0 Ghz. Issue: - I did a clean Mavericks install, then installed Yosemite over it - It worked well for a few weeks, then the screen glitches and freezes all of a sudden - Try to reboot, hear the chime, click my username, enter password - The load bar goes to about a quarter to half, then the screen goes grey and does nothing Things I've tried: 1 Boot with the option key and tried to run the Mavericks installer from an external HD. This makes the screen glitch in different ways before going grey. 2 Boot with command+R . This gives me the load bar, no recovery menu 3 Boot with internet recovery. This gives me the globe, with the load bar going 4..3....2...1... then grey I'm out of ideas here. I'd like to get this computer to run again. No files to be saved or anything, but I'd just like to get it up, Mavericks or Yosemite. Can anyone help me crack this nut? Thanks again.