iMac does Chime noise, but blacks out

[Fade]

So, I switch it on, it makes noises as usual (the operating inside the computer) and does the Chime start up noise, then just stays black?

Any suggestions?..

 

[Hurt]

My MacBook does this, but sometimes the display will randomly turn off as well. No clue how to fix it, and it may be an entirely different issue. If you find something out please let me know, good luck solving this!

 

[Fade]

My MacBook does this, but sometimes the display will randomly turn off as well. No clue how to fix it, and it may be an entirely different issue. If you find something out please let me know, good luck solving this!

Well how do you solve it when it happens?

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I got it to work thanks so someone on another forum!