Did you import from another forum application?
I agree with Brogan. Check the collations in your database. You can check the collations using a program like
phpmyadmin which many hosts preinstall for you. Once inside of phpmyadmin you can view the collations. All tables and fields should be
utf8_general_ci:
View attachment 23014
View attachment 23015
Also try rebuilding your forum info:
Admin CP -> Tools -> Rebuild Caches -> Rebuild Forum Information