Do you have Microsoft Office 2007 installed? The issue you describe crops up in OE after installing Office 2007.
Since OE does not have a spell checker, it relies on spell check installed by MS Office
Programs. If you had a previous version of Office and upgraded, the new 2007 files are incompatible with
OE. Microsoft is aware of the issue but has no plans to correct it. If you want to use spell check with OE, you will have to
1) uninstall Office 2007 and go back to a previous version
2) install a third-party spell check for use with OE. This is the better option, especially if you purchased Office 2007. You don't want to uninstall it and end up wasting your money after paying for it.
Microsoft article about the issue:http://support.microsoft.com/kb/932974
And from AnswersThatWork-Outlook Express Spell Check is French after Office 2007 install