Thank you very much. I will look into that. I appreciate your help and I will try to pay it forward.
Pthei
So, basically your OS (which is/was El Capitan) won't load... You obviously want to fix that, and you also want to replace the OS with an older version...
You have several options depending on several factors.
1. Do you still have the stuff that came with your computer- specifically the OS installation DVDs for Snow Leopard? If so, start off by re-installing Snow Leopard so at least you have a working Mac.
2. If not, do you have (or have access to) another Mac? Or any other working computer? (I'm assuming yes since you're corresponding here- but of course that could be via phone). If not, that may limit your options.
3. You need to obtain the installer for Mountain Lion somehow. As far as I know, beginning with Mountain Lion Apple stopped selling their OSes on physical media (DVDs/discs)- they just sold it in the app store. So you probably won't be able to find any "hard" copies for sale- unless the did include a back-up copy on some kind of physical media with some of their computers that someone is willing to sell. However, you should be able to find a downloadable version somewhere online if you search thoroughly...
4. If you haven't re-installed Snow Leopard to get your MacBook running again, you will need either a blank DVD (dual-layer—8GB capacity) or a USB flash drive or memory card (with USB adapter) with at least 8GB capacity (the DVD is definitely the slowest option!) to boot up and install the OS from.
Here are some instructions on how to create the installer:
https://mac-how-to.gadgethacks.com/...vd-usb-drive-os-x-10-8-mountain-lion-0138303/
https://itekblog.com/create-os-x-mountain-lion-bootable-usb-from-windows/
Just a word of caution: Even if you are able to get ahold of a Mountain Lion installer, I would recommend you carefully consider whether you really want to install it. Don't get me wrong, I love it- I'm still using it! But it is no longer supported by Apple at all, so any security weaknesses will never be fixed, plus more and more updates of applications do not support ML. Unless there is some software that you own and must use which is only compatible with Mountain Lion, I really think you would be better off with one of the newer releases.
I hope you are able to get your Mac back up and running ASAP!