If your WordPress blog has stopped working with an “It doesn’t look like you’ve installed WP yet. Try running install.php” error and you’re using mysql, make sure you didn’t accidentially upgrade from mysql 4.x to 5.x. Starting with version 5, mysql does no longer trim spaces from varbinary fields, however, WordPress expects that (incorrect) behavior.
Until the WordPress guys fix the table structure (i.e. use varchar instead of varbinary fields for string fields), you’ll have to go with mysql 4.x.
