Joomla 1.5 comes with UTF character set. Howver MySQL database might get installed with latin1_swedish_ci collation.

This may casue probles with displaying non latin characters, for example cyrillic.

In order to make Joomla work properly,  one needs to set in phpMyAdmin MySQL connection collation: UTF-8 Unicode (utf8)

and also to runthe following SQL query for each table:

ALTER TABLE your_table_name CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;

Do not forget to back the database if it already has data.

If you had comments option opened in your Word Press blog, spam engines will find them and will try to post comments. If you disable comment option, the old posts will still be opened for spam.

Here are more IP addresses where spammers come from:

203.69.39.251 
200.88.223.99
207.44.238.95
190.129.118.1
82.148.98.34
60.190.223.77
222.240.208.14