iMac shuts down after welcome Intro

When i press the power button i see the apple logo, then it loads the mouse on the upper left side of the screen.

After that i see the welcome screen intro, after that intro the screen becomes black, not sure if turns off or not. i don't hear any sound or something running.

I tried to boot from usb it was stuck at the grey boot screen with the apple logo

what could be the problem?

P.S i'm thinking about turning the imac to a screen with an lcd controller if couldn't find a solution.

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Do you see the loading progress bar and does it shut down at about midway? PS stop thinking until you have some idea of what is wrong!

crwdns2893770:0crwdnd2893770:0crwdne2893770:0

It shuts down at the end of the welcome screen intro.

crwdns2893770:0crwdnd2893770:0crwdne2893770:0

Could it be a HDD/SSD Failure, I had a 27" iMac that would begin booting, just reach welcome and then fail. I replaced the disk with a SSD and re-installed the OS. I'm not sure that is your problem, but it's a suggestion.

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Can you record a video or take pictures?

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i have usb boot disk on key with osx on it, when i try to boot from usb the screen is grey and stuck with no apple logo, progress bar is nowhere near to be found

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