iMac a1225 doesn't boot

[satmatic]

Hello guys, I installed a new HDD into an old iMac (2012) and I can't install any kind of OS.

I have many USB's with Capitan, Mavericks and High Sierra, and a CD with Snow Leopard.

I'm working with a functional Windows keyboard and when I press some kind of keyboard combination it just does nothing and takes me to a flashing interrogant folder, unless i pres C, that makes a cursor show up and the screen stays blank.

I know windows logo is cmd and alt is options, having this in mind none of this worked to me, already tried to reset ram and i pulled the power like 10 times.

Any suggestions?

 

[Fishrrman]

Try another keyboard.

 

[satmatic]

It's not the keyboard, as I said it reacts when I press C but instad of the blinking folder it just shows the cursor on a white screen and I left it like this for hours and nothing. Anyways I tried swapping into 4 different keyboards with no results.
PD: I was able to run a boot utility from a bootable usb but I tried having this started with all of the OS usb's and it just says no bootable system found, and I know those work.

 

[nambuccaheadsau]

Try a Mac keyboard.

Then pop in your whatever USB, assume it is a thumb drive, reboot and hold down Option immediately after the chime and see if the whatever is bootable