I've been working on this for hours and I have to go to bed, but I'll check back in about 10 hours (hoping someone bright takes pity on my plight). Short version: My posts are still there, but I get a "not found" error when I load the index.php
I was re-starting my blog, so I deleted all of the entries. I added a real entry, then clicked on view site--I got the message:
Apologies. But something you were looking for just can't be found. Please have a look around and try searching for what you're looking for.
(I think that this is a message generated by my theme because I could not find it in the troubleshooting forums. It's basically the one you get when no posts are found [I think])
I added another message, then two more, all without effect. They show up on the preview screen at the bottom of the Edit Post page just fine and all messages are still visible in the pane at the bottom. I can also view them just fine by going into the Manage/Posts and clicking on View.
I upgraded from 2.0x to 2.1 hoping the problem would go away. No such luck.
I saw some posts related to Permalinhks and .htaccess, so I put a post on the clipboard, chamged my permalink structure to the one based on /year/mo/day/title, revised my .htaccess as specified and looked at it again. No luck.
There's nothing in my blog that is secret or not backed up. If you know of a further diagnostic that you can do, my blog is at kencomer.com/index.php and I have created user tempadmin with password tempadmin for ready access.
Now comes the deep dark confession: I have changed some of the PHP. I am 99.9% certain that I saw the page display correctly since the last change I made to the CSS and the PHP definitely did not change since the last time it successfully loaded.