System install on a mid-2010 iMac

LSowell wrote:

Yes I do have access to my laptop.

I just read the link from padams and not comfortable using Terminal commands to create a bootable USB.

The system disks that shipped with this machine are in brand-new condition and have never been out of the packaging until now. But the machine does not recognize either one (and that includes holding the C key during startup).

I really appreciate everyone help, thank you.

Creating an OS X El Capitan bootable installer is the only way. If you properly follow the steps here: How to create a bootable installer for macOS - Apple Support, it is simple. You don't type anything into the Terminal, you just copy and paste the command Apple gives you.

If you have access to a Mid 2018 or older Mac you could create a USB-Installer. https://support.apple.com/en-us/HT201372

Could you post a copy of the first line or two of the exact error message? I haven't heard of that one before.

LSowell wrote:

Yes I do have access to my laptop.

Does that Mac have an optical drive? What year? What about ports? FireWire? USB?

What Jack was getting at is using Target Disk Mode to access the 2010 drive from the other computer. I've installed operating systems from opticals disks in one MAc to another with a dead optical drive. And no Terminal commands!

See: Transfer files between two Mac computers using target disk mode - Apple Support

What Jack was getting at is using Target Disk Mode to access the 2010 drive from the other computer. I've installed operating systems from opticals disks in one MAc to another with a dead optical drive. And no Terminal commands!

Actually, I was getting at creating an OS X El Capitan bootable installer. The OS X Recovery built-in on these Mac computers (like the OP is using) has a built-in expiry for the software, and that is why it cannot install. However, the version of OS X El Capitan available from Apple (How to get old versions of macOS - Apple Support) does not have the expiry, and the older software is still valid, so a bootable installer works.

In addition, in my past experience at least (so not scientific at all), in more recent versions of macOS/OS X, you cannot install macOS from Target Disk Mode. But again, I have not done it recently. I may be remembering incorrectly.

Jack

I get messages to contact the manufacturer of the software I am trying to install (Apple?) or just plain errors.

That may be a clue, When your Mom had this iMac, was it a "managed device" as in a school or business setting? If so, that could be the issue. Managed computers have school or company software installed to limit how much access users have to system functions.

The system disks that shipped with this machine are in brand-new condition and have never been out of the packaging until now. But the machine does not recognize either one (and that includes holding the C key during startup).

CD/DVD disc labels facing the user when inserted, not the back of the iMac?

Any chance you have a CD drive cleaning disc that you can run through the machine a time or two?

Also, as Jack-19 posts, creating the bootable USB installer only looks complicated on paper. If you take it one step at a time using copy/paste commands I'm sure you can get through it.

Do you have access to another Mac?