Mr Randall wrote:
Here's a screenshot of my Applications folder and the Mail folder.....

I took a look at your screenshot, Mr Randall & you did not do what WZZZ told you you must do. You did not delete the version 4.6 "Mail.app" icon that is in your Applications folder. I can tell that it's version 4.6 because of its small filesize & the fact that it's got a generic Apple icon, not the Apple Mail icon. And FYI, DESPITE THE FACT that it says it's version 4.6, this particular one, at this stage of the game for you, is GARBAGE. So DUMP IT.
So your very first Step #1 is this, Mr Randall: DELETE THAT MAIL ICON IN YOUR APPLICATIONS FOLDER.
Secondly, I see that in your Applications folder that you've also got a folder there called "Mail." That Mail folder SHOULD NOT be there. That Mail folder, which contains all of your emails, should be located in the "[username] / Library" folder and ONLY in there (see screenshot). So MOVE IT.
And by the way, Mr Randall:
Mr Randall wrote:
Here's a screenshot of my Applications folder and the Mail folder.....
That second window in your screenshot is NOT a screenshot of, as you stated it is of, of your "Mail" folder (which somehow mysteriously got in there).
That second window is a of the CONTENTS of that half-baked, garbage Mail.app v4.6 "application" that you didn't get rid of that WZZZ told you you had to delete but which you did not do.

Follow our directions & don't experiment & don't do things that you are not 100% sure of doing, as it sounds to me as though you are not all that savvy with the Mac OS; you sound to me that you know just enough to be dangerous for yourself (as we Gateway Tech Support people used to term some of the Gateway customers we used to deal with back in the olden days).
Just follow the steps that I posted here in a previous post in this thread TO THE LETTER and ONLY those 5 steps & you'll get your Mail to work again.
And get that "Mail" folder OUT of your Applications folder and put it back where it belongs!!
KK