Remove ICQ/MSN/YAHOO/BIO etc. of around 1600 users via Phpmyadmin.

[kh99]

I can't think of any reason offhand that you couldn't change the username field directly, except that I think there are other tables that have a username field (like the thread last poster) that won't be changed.

You should be able to change the password, but it's hashed. I think you'd need to do something like:

UPDATE user set password=MD5(CONCAT(MD5('XXYYZZ1122'),salt))

but I haven't tested this. Be careful because as I'm sure you're aware, if it doesn't work you won't be able to log in either (unless you add a WHERE so that your password isn't changed).