Try this query in phpmyadmin:
PHP Code:
UPDATE user
set password = MD5(concat(MD5('<typenewpasswordhere>'), user.salt))
WHERE userid = <useridnumber>;
Replace typenewpasswordhere with the password you wish to use, replace useridnumber with the actual # i.e. if the members user is is 55 you would enter in 55

.
If that doesn't reset the password then something else is afoot and we'll need to look elsewhere such as uploading tools.php etc.