I have a problem with a web I'm developing. It's made in Joomla 1.5 (PHP-made CMS) which uses utf-8.

The problem is that every special character like tildes are not displayed correctly. If I clean the Joomla cache, the content is displayed right, and Firefox says it's being displayed as Unicode (UTF-8), but the next times it's shown with those weird characters once again, and I see that Firefox is using the ISO-8859-1 charset instead.

What can I do to fix this?

And another question, does anybody know about a Windows application which allows me to quickly check the charset in which all the files of a website have been encoded? Perhaps if some working mate edited a file and saved it as ANSI or something like that, which might be causing the error, I would have a tool that quickly helped me check that.