I run a popular book blog and a few days ago I noticed all my plugins had been turned off. I checked and there was a new user account (called "wpadmin") that had been created with admin access. I cancelled the account and reactivated my akismet, etc., but then other strange things started to happen. All of my Pages disappeared and now I can't post. I installed 2.3.3 and still nothing. Further, the buttons in the editor have switched to text only versions resembling the basic editor that comes with a WordPress.com account. I can write a post and it will auto save, but if I try to save or post it, it goes to "post.php" and nothing happens -- just a white page. People can still comment normally on existing posts though.
Can anyone tell me what happened?