High Sierra grey screen

[TVreporter]

I have an iMac 2011 which was running High Sierra well.

But yesterday the screen suddenly went white. Now in reboot the screen goes grey with the logo and goes through the status bar but then goes to a complete grey screen and won’t load.

I’ve tried resetting NVRam and SMC and other usual steps.

When I hit option I get HD, HD recovery and my Time machine but with each option I select it just goes to the grey screen.

I got into safe mode once and scanned utility desk but nothing. However the graphics were loading slow.

Now I can’t get safe mode anymore.

Any suggestions? Is it hardware or software? I am panicking here!

 

[Mac Hammer Fan]

Did you try the apple hardware test? Disconnect all external devices except keyboard and mouse. Boot while pressing "D".

 

[TVreporter]

Did you try the apple hardware test? Disconnect all external devices except keyboard and mouse. Boot while pressing "D".

I tried that and it loaded the 3 min test “no trouble found”

Going to try extended test now

Wish I could post pics on here to show what’s happening

 

[TVreporter]

No problems reported with the hardware test...

Why can’t it enter safe or recovery modes?

 

[TVreporter]

Anyone with any advice

Option gives me:
Macintosh HD
Recovery 10.13.2
Backup (time machine)

When I chose either one it goes to a compete grey/white screen and does nothing .

Have I lost my content? I do have my photos on ICloud and my Apple TV 3 still seems to read the photo screen saver from the Mac...

Someone please help!!

 

[Mac Hammer Fan]

Try booting from an external bootable disk. Or ask a friend to make a bootable USB installer. Do you also have a grey screen in this case?

 

[TVreporter]

Try booting from an external bootable disk. Or ask a friend to make a bootable USB installer. Do you also have a grey screen in this case?

Does the drive need to be formatted any specific way to just download the installer? Or can any drive do it? Don’t have any friends with macs or life anywhere near an Apple Store.

Can I download Sierra installer to downgrade from high?

 

[TVreporter]

I tried Control V and at the end I got these messages

Anyone able to help? It just went straight to a complete grey screen again

I’m so frustrated with all of this!