installing Apple a1224 iMac

Hi all,

i am new to apple. I got a used iMac from a friend. Its model is a1224 from early 2008. My friend reset it to destroy all of his data, so the iMac is just able to boot up to emergency mode.

The original disc is missing. I tried several things (over 4 days of troubleshooting) to get it work, but no success unitl now.

Here are some ways, I tried:

1) reinstall El Capitan:

Mac OS X Utilities option to reinstall OS X El Capitan gets stuck after i typed in my apple id. The message is "app store currently not available, please try again later".

The internet connection has been established every time before i tried to reinstall. Start volume has been repaired too.

2) install from bootable USB:

Another friend supported me, he just created a bootable USB El Capitan from his Macbook

The USB is available under "Disk Utility". So just restartet the iMac and pressed "option" after Chirme to get to boot selector. But after i chose the USB the iMac just boot from harddisc to emergency.

3) bought new DVD Mac OS X El Capitan

The installation process finally just spun up. The installation bar is at 100% after 4 hours.

I reset the device after 26(!) hours of further installation. It seemed that the installation just froze on some point.

After some googling i reset the nvram and repeated the steps too, but same status after all.

Help appreciated

Marie