imac 24" doesn't start

[diddi969]

Hi everyone
i have a big problem with my iMac.
He won't boot via harddrive/cd.
He always stucks at the spinning wheel and gets a black screen later he is rebooting again.

I tried fsck -y , change ram nothin happened.
Thanks for help

 

[simsaladimbamba]

Have you tried any of these steps except the ones you mentioned?

Mac doesn't boot

Resolve startup issues and perform disk maintenance with Disk Utility and fsck

Troubleshooting: My computer won't turn on

A flashing question mark appears when you start your Mac​

 

[diddi969]

Have you tried any of these steps except the ones you mentioned?

Mac doesn't boot

Resolve startup issues and perform disk maintenance with Disk Utility and fsck

Troubleshooting: My computer won't turn on

A flashing question mark appears when you start your Mac​

yes I already did all these steps.
meanwhile there is somethimes a big pixeled black/white/grey combination of pixels on the left, after the wheel stops spinning.
Iam very confused
This happend after I deleted the ACLs via command+S terminal.
It shows:
bootcachecontrol..... not found

 

[diddi969]

yes I already did all these steps.
meanwhile there is somethimes a big pixeled black/white/grey combination of pixels on the left, after the wheel stops spinning.
Iam very confused
This happend after I deleted the ACLs via command+S terminal.
It shows:
bootcachecontrol..... not found

after a lot of research I have some questions about bootcachecontrol.
Is the bootcache.playlist installed on the hard drive?
Iam totally confused because with no harddrive connected It also stucks on the spinning while when I want to start via install-cd.
The only thing which is working -> the Hardware-Test and it shows no faults.