Hey guys @nick and @andrewsawesome
Good news!
I followed nick’s tips and opened the machine. the optical driver was just disconnected for some reason. It is also bondi blue/blueberry color (the imac is tangerine) so I think it was opened before. I connected and it works perfectly (opening and rotating - tried with a music cd) but I don’t know the capacity to read and reinstall the macos since I can’t test out this drive cause the mac is still locked.
Ok, now I need a CD with a Restore Software in it to try my luck. I never did this before, so tomorrow I’m going to search someone with a notebook with cd drive to burn this iso CD.
Also, I didn’t find a tutorial of how to burn this bootable cd from a .iso file. Do you know anyone?