@cdberkman - if you've installed hundreds of plugins and 9 times out of 10 they don't work, you have to consider if there's an issue on your end. We've been doing WordPress since 2005 and building websites for 17 years. I don't know your entire situation, but 2 things that resonate with me are the fact that (it sounds like) you've been on the same shared webhost server for a very long time. Also, it sounds like you've possibly been on the same WordPress database for a very long time (updated again and again through multiple versions).
I don't know your experience level with either development or WordPress, but nearly every time you install a plugin you add database entries (and in most cases) new tables. Even if you just try it for a few minutes, and then delete it (the tables and entries remain). The standard WP install has less than a dozen db tables - if you've installed hundreds of plugins - you could have 80-100+ tables, in additional to hundreds of extra records in the options tables. Plugins are written by different developers that set their own naming conventions (that sometimes conflict). All I'm saying is - we see more conflicts with a setup like this, than a new WP installation. We also have 10x more issues with a WP website that has been upgraded over time through multiple versions, than a fresh install. The same can be said for an older webserver (in most cases).
You may or may not want to do this, but (if we were you) we would get a $5 account at hostgator on a new server, export your db and content - create a new db on hostgator, import your db and content, and add fresh versions of your theme and plugins one by one. I guarantee that updated version of your website will run completely different. We only know this because we fixed hacked websites all the time - and this is how we do it (export content, fresh db). We noticed how much better the sites run (and the excessive db tables on existing sites) - so we started doing it for aging sites needing a tuneup.
Whether you love your webhost or not, the hardware and OS might be aging and patched to infinity and beyond (as well as your WordPress db).
In regards to the plugin and previous version, the very old version from Semper FI is still available - bugs, security holes, and all. We didn't take over his version, we forked his plugin into a new one.