turkish character problem in forum

Hi!
In my forum (http://forum.csharpturk.net/default.asp) turkish charecters isn't displayed correctly. ex 'ö' instead of 'ö'
Interesting one is that in some topics there is no problem at some of them there is. For example whole main forum page is incorrect. At subforum some of topics are correct some of them not.

I searched in turkish forums, i tried some of them including changing some code in  browser_page_encoding_inc.asp page.  I added turkish character set "windows-1254" but proble is going on.

Can anyone help me i will be so appreciated ? I am out of my mind right now. It seems easy but i can' figure it out

I found
replace meta tags with this;

<meta http-equiv="content-type" content="text/html; charset=iso-8859-9"/>
<meta http-equiv="content-language" content="TR"/>

windows-1254 is not good for Turkish