I had just installed WordPress 3.1.3, and tried to activate the theme "Grey Opaque" 1.2.0 by H.-Peter Pfeufer and lost all functions of the blog, twice. All any blog address returned was a blank white page.
I erased the directory and uploaded the files and re-installed. Installing "Grey Opaque" seemed OK, but activating it made all pages blank white. I like the theme, is there a fix for that? Chip Bennett said to turn on "wp-debug" in the "wp-config.pgp" file and contact you.
Before trying it again, though, is there a set of directories or files I can save a copy of, so I only need to restore those to return the blog to functionality? I don't want to completely re-install if possible. I've done a little work with another theme, uploading a masthead image, defining categories and entering a couple posts.