Hey! Since yesterday I've been having major issues with my 15" Retina MacBook Pro (mid 2012 model). When I boot it, the screen is black (no backlight: Apple logo doesn't light up). I do hear the startup chime, and it actually does proceed to boot, but the screen stays dark. After a while, I can hear ticks as I adjust the volume, I can adjust the keyboard backlighting, etc. After it boots, the fans stay on at full speed. I did a PRAM and SMC reset, both to no effect. After lots of fiddling with plugging and unplugging an HDMI cable to an external monitor, I eventually got the screen to turn on. Most things seem functional, besides it being a bit sluggish and the fans still stay at full speed (and there seems to be a LOT of battery drain). I'm using gfxCardStatus and I notice it isn't really able to switch to the discrete GPU anymore. Does anyone recognize this issue? I suspect it's a hardware issue (broken GPU? broken connection to GPU?), are there any more tests I can do? I notice in the system report at Graphics/Displays, it only gives me something about the integrated "Intel HD Graphics 4000". Can anyone else with the same model rMBP verify whether this is normal?