TheBluesBlogger contacted me off forum .. and Ive fixed his site.
There were quite a few things going on.
1. However the new files got on his site, they was corruption. The first clue to that was that the wordpress logo image that's displayed on the login page was scrambled.
2. The wp-includes and the wp-content dirs both returned 404s and 403s (it went back and forth).
3. Once #3 was fixed, the chosen theme's style.css still couldnt be loaded in a browser, even though all of the associated PHP files could be.
5. There was an .htaccess inside wp-content/ with "deny all' in it. (More of a cause and not a problem.)
6. (Ive lost count)
7. The wp-config.php had NOT been upgraded to reflect the keys introduced in 2.6.
8. There were all sorts (100s) of lone plugin files uploaded to the root of wp-content/ and thats probably how the .htaccess got introduced. Its part of a plugin.. no doubt.
Obviously I fixed all of the above, uploading ALL fresh core files.. I also deleted ALL of the wp-cache files, and during my editing of the wp-config.php removed the line that enables it.
I moved ALL of the plugins into another directory, just to temporarily eliminate any problems they might be causing.
Inside the theme directory was a style.css~ -- Once the 403s and 404s were fixed, deleting THAT file allowed the style.css to load properly.
Once that happened, I moved back all of the plugins.
The site's fixed, and I didnt even need access to wp-admin to do it.
Of course, I did some minor housekeeping too.
