Hi, So I tried to do a little research before I posted anywhere but I've not found many with the same issue as me. I recently was having problems with the screen going black / off after working for a while. I was working with it on the lowest brightness as any higher would just make the screen cut out and I'd have to restart. I had attributed all of the above overheating and installed a program to manually control the fans which really helped out. I left my iMac off for a few days whilst I was away and upon return it wont boot up. I hear the chime and see the logo followed by loading bar but around the around half way to 3/4 full the screen goes white for a few seconds and then turns off & randomly blinks on. When it blinks I can see the loading bar where it got up to and a spinning wheel (not the multi colored one but white with lines) I have reset the PRAM and SMC and can see my HD and SSD to boot from when I boot with option. I'm on 10.11.1 I think. Any help or information would be great!