Prohibited Symbol when launching Recovery Image on OS X El Capitan

There were no Mid 2007 iMacs with SSDs. I am assuming you meant HDD / hard disk / startup drive etc.

In any event reinstalling OS X from disc is the correct action to take. It will recreate the Recovery image.

Does this 2007 iMac still boot normally? If so, then create a bootable macOS 10.11 El Capitan USB installer now while you still can by using the instructions in the following Apple article:

Create a bootable installer for macOS - Apple Support

There is a link within that article with instructions for downloading & extracting the El Capitan installer...read them carefully since there are multiple steps.

My concern for a 2007 iMac is the health of the Hard Drive, or did you have it replaced with an SSD since you named it "Macintosh SSD"? If it is an SSD, how long has it been installed and have there been any issues with it? I'm also concerned if a third party SSD is installed because not all SSDs are compatible plus there are a lot of awful SSDs out there these days that may not function very well.

The 2007 Mac does not support Recovery. Your only hope of getting El Capitan on that machine is through a USB installer key that was created from a Mac that already has it on. At this point since Apple's Mac App Store is not available for users with pre-Sierra Mac OS, that's probably your only choice.

applusr22 wrote:

Mine was replaced with a Lexar 128GB SSD.

That is an important detail. Since that iMac's original hard disk was replaced, you need to reinstall OS X from disc. As I wrote. Specifically, that iMac's original, grey, System Install DVD. Then, upgrade as desired.

That will recreate the Recovery partition, and restore the ability to boot Recovery.

A "bootable USB installer" is also an option, but you would need to have created one already.

If that Mac's previous owner did not include that disc, obtain it from him or her. Those two discs must accompany the Macs they shipped with from cradle to grave. Without it your options become limited.

Good point. If command-R on a wired keyboard fails to yield a boot volume, then the volume either never had Lion or later installed, or is beyond normal repair. You can try the Disk Utility from a Snow Leopard installer disc booting with the Option key on a wired keyboard. Utilities menu on the installer has Disk Utility and repair disk.

Windows keyboards use Windows logo key instalead of Command.