I was facing the similar problem – no screen options in new posts, permanent links were not working (and “no posts found” problem occured when permanent links were different from default).
I tried to make a local copy in virtual machine – everything was OK. Replaced files, repaired database.
Problem was different: I found malicious .htaccess directives in top directory redirecting part of PHP URLs somewhere.
Once I deleted all unwanted stuff, it works like a charm.
