When you turn on the iMac (iMac Intel 21.5 "EMC 2428, Model A1311 / Mid 2011)
I get the beep and after some time a blinking question mark appears in the folder.
I tried all of the keyboard shortcuts on the Mac wireless keyboard and the Windows USB keyboard, but it did not work.
Then I changed the hard drive for a new SSD, but that did not change anything.
What I have tried:
1) All combination keys that I could think of. On the original Mac wireless keyboard and the Windows USB keyboard.
D, N, T, possibility, command + R, possibility + command + P + R, shift, command + S, command + V
Whichever combination I use has no effect on the startup process and after a while a question mark appears.
2) I insert a USB stick with a bootable system and also system CD, but the combination key did not work. I can not eject a CD with the eject button on the keyboard. I can only eject the mouse at startup.
3) I have replaced the batteries on the keyboard, and when I turn on the side power switch, a green LED may light up briefly. The Caps Lock LED does not work, but I do not remember that this ever worked.
4) I have removed all but one RAM memory.
I spent the last few days researching the problem, but all point to a bad disk I've already replaced. What could be a problem? Can I try something else?