I had that happen or something like that happen. What I did is i went into my database and erased everything and just started over like i had never used it. unless someone tells you how to fix it this is what i did.
Erase everything dealing with wordpress and start fresh
I keep these around in a text file when I want to get rid of all the table in my database (for testing). I use myPhpAdmin to do paste these into the Run SQL query window.
DROP TABLE wp_categories
;
DROP TABLE wp_comments
;
DROP TABLE wp_linkcategories
;
DROP TABLE wp_links
;
DROP TABLE wp_options
;
DROP TABLE wp_post2cat
;
DROP TABLE wp_postmeta
;
DROP TABLE wp_posts
;
DROP TABLE wp_users
;
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