Okay, I've gotten myself into a real pickle here, and I'm completely stumped. I've been at it with a sick feeling in my stomach for hours and gotten nowhere.
Here's what happened:
I had a custom function in my theme that wasn't working correctly. I wanted to delete an image from a slider on the homepage, and it wasn't popping open for me to edit it.
So, I figure, let's find that thing in the database and get rid of it. Do I make a backup at this point? No. I figure I can always just keep track of any change I make and undo it if necessary, and no harm done.
Well, okay, I guess it doesn't always work that way. I removed the offending values from the database manually, and I revisited my page. Everything was broken. Undo, undo! So I re-inserted the offending values right back where they were (90% sure of that; I know, that's not great, but it seemed straight-forward enough). These were found in the "wp_options" table.
So, turns out, if the site is working perfectly, and I change one character there, even if I change it back, somehow it breaks the front page. Just the front page (well, it resets all theme settings, but I rebuilt them, and then I made a backup, so I tested this a bit so that I could make absolutely certain that this was the cause). All the other pages are fine. My question is: how does it know?!?!?
Now, when I say "broken", here's what I mean. It's not a WSOD. There are no PHP errors logged. A database repair & optimization tool doesn't find any errors. The page header and footer loads. But the page content, whether it's a static page or a post page, fails to load.
I've learned a very important lesson and I will surely never do it again, but can someone PLEASE, please help a poor idiot? Is this a WordPress thing? Is it a MySQL thing? Would it help to reinstall the theme?
The site, with its broken front page:
A working link: