Did you made a backup of the extension XPI files?

• http://kb.mozillazine.org/Installing_extensions
• https://support.mozilla.org/kb/customize-firefox-with-add-ons-plugins-and-extensions

Yes, I saved the whole file of all of the extentions but I can't figure out how to reinstall them. I read your suggestions but I still can't solve the problem as much of the terminology is not familiar.

You can only install extensions locally if you extract all the extension from that archive if you placed them in a ZIP archive and either use File > Open File or drag the extension in a Firefox window.
If have have the extensions in the {GUID}.xpi or <email>.xpi version then you can also copy those .xpi files to the extensions folder in the Firefox Profile Folder to have Firefox install them on a next start.
This won't work for the regular name of the extension as downloaded from the Add-ons page.
If the extensions folder doesn't exist then create the extensions folder.

It does not appear I am doing this right. First I open a Firefox window and then I open the old Firefox files and drag them onto the Firefox window and the files are on window. Then what? This process is obviously beyond my skill level. I'm sorry to be so daft but it appears I need a lot of hand holding in this task.

You can only install extension files that have a .xpi file extension that way.

Can you attach a screenshot to show what kind of files that you try to install?

• http://en.wikipedia.org/wiki/Screenshot
• https://support.mozilla.org/kb/how-do-i-create-screenshot-my-problem

Use a compressed image type like PNG or JPG to save the screenshot.