I've just been through the same mess, details description of issue is as follow:
- Red horizontal lines display right after you startup, it will go on to show you the apple (still in red horizontal lines), then it show the gray screen, and your fans start running like crazy.
If you switch to Windows OS you'll be able to run on safe-mode, and the screen look like... well you know
My conclusion is the RAM, not normal issue, a special RAM issue. I followed these steps and fixed it:
Take out one RAM
- Reboot on recovery mode, (press and hold: command + R)
- Then it will display a crappy screen again still the apple sign
- Then it will turn blue.
Don't panic, shut it down this time do a PRAM reset (press and hole command + option + P + R)
If the RAM you are using is ok, everything should back to normal. If not, then replace it with the one you just took out and do the whole thing again.
I tried command + R alone, and it not work. I then tried PRAM reset (press and hole command + option + P + R) alone, it did not work. Only when I combined them, then it worked!
Also, it you put the faulty RAM in and take it out, even though you are sure the RAM is OK, the problem still exist without doing the process that I just described
Hope this helps, and stop paying Apple for non-sense things.
P/S: I keep wondering why all MacBook's suddenly have the same issue at the similar period. If Apple do this on purpose to make us purchase new stuff?