All of a sudden I can't log into my admin for one of my sites...
...THIS IS *NOT* A PASSWORD RE-SET PROBLEM!!
It may not seem like it, but actually, I think that's exactly what you need to do.
"I just tried the last thing I can do to fix this according to the help files on login trouble"
No, you're not quite at that point yet.
If you are the admin, and you can no longer access your dashboard, you need to access the database tables (wp_users), directly and find out why. Repair the admin user name and password so that you can have access again. It also might reveal information about what happened. While you are there, I suggest you look around for users you don't recognize, and admin accounts that should not be there.
The links we gave you contain information relevant to several methods of accessing your database. I personally think that if you have phpMyAdmin available to you, that might be the easiest method by which to examine your user database and repair your admin account (follow one of the tutorials in the links). You will, however, as a first step, have to find out what MySql management tools are available to you through your hosting service, and choose the correct course of action from there.