I cannot get out of recovery mode (OS X Utilities) by resetting or reinstalling the OS

Question

I bought a used iMac and when I turn it on I am shown the OS X Utilities screen. I would like to install the operating system but I cannot do so.

I have tried everything suggested on other questions on this topic:

1. Factory reset

I.e. formatting the hard drive (as instructed by Apple) and restarting. According to the Apple website, this was supposed to bring up the country selection screen, but it didn't. It simply takes me back to OS X Utilities.

2. Resintall OS X

There is an option to reinstall OS X El Capitan. After signing into iCloud (with a new account I had to make for this - I did not have one before) I get the error message "This item is temporarily unavailable". I have Googled this and tried the many fixes to no avail. Apparently the original user's iCloud account should be used, but I do not have access to this, nor do I want them to be linked to this computer.

3. Other macOS Recovery modes

Apple gives key combinations for other recovery options. I have tried all three of them as instructed but I am always asked to enter the iCloud details.

4. Boot from CD

I do not have the original CD with the operating system on it, nor do I have access to a computer that can burn a bootable disk. (This is not an option I want to consider to be honest - resetting an Apple computer doesn't require this according to the many guides and videos on this issue.)

Screenshots of hard drive formatting:

Screenshot of iCloud error:

Answer 1

On an 08 iMac, your options will be limited if the previous owner didn't correctly run through the reset procedure, leaving you with a nice, simple sign-in to take over the Mac as your own.

Part of the procedure is for them to sign in on their own existing App Store account & reinstall a clean OS that they are already associated with, as 'purchaser'. if they exit the process after install but before sign-in, then it's ready to transfer ownership.
Without that, you're left with trying to sign in as a new user with no previous purchase history & no access to anything other than the very latest macOS - not good if your machine can't run that.

Additionally, an 08 is not capable of running Internet Recovery, so automatic access to the correct installer is not possible.

Theoretically, you could boot an 08 from USB, but in practise I've never managed to achieve that, earliest I've managed to do that on was an 09.
This may leave you with only an install CD as your working method, although it's always worth trying to get a USB key to work first.

You are going to have to access the installer from another computer & burn/flash your startup medium from there.

Answer 2

Enough users have post a question regarding the free upgrade from Snow Leopard to El Capitan that this should not be a hard question to answer. In the case, the process for downloading El Captan works differently than what you posted in your question. This is for Snow Leopard users who wish to upgrade to El Capitan, which is the latest version of OS X (macOS) that Apple released for the 2008 iMacs.

1. If necessary, use a newer Mac to create a Apple ID that can be use at the Apps Store. Although, it appears you may not need to sign in to download El Capitan.
2. If necessary, upgrade older iMac to version 10.6.8 of Snow Leopard. The Combo update can be found at https://support.apple.com/kb/DL1399?viewlocale=en_US&locale=en_US. However, you can also upgrade to version 10.6.8 by just downloading the available updates. Technically, you might be OK, if you have 10.6.6 or newer version of Snow Leopard.
3. Enter this address: https://itunes.apple.com/app/os-x-el-capitan/id1147835434?mt=12 into Safari on the iMac. You should be able to download El Capitan.
4. Follow the instructions at https://support.apple.com/en-us/HT201372 to create a bootable USB El Capitan installer.
5. Boot from the USB installer and use the Disk Utility to erase the internal drive.
6. Install El Capitan.

Actually, you do not need a flash drive. You could just run the downloaded El Capitan installer application to upgrade. This would allow you to skip steps 4 and 5.