I am using Windows XP with Office 2003 Professional. When I want to use
Equation Editor, the following message prompted.

Microsoft Office Word can't start the application required to open this
object.
An error occurred and this feature is no longer functioning properly. Would
you like to repair this feature now?

I have checked all the related documents online, and found that Norton
Anti-virus may cause this problem. However, I don't have any Norton's
Sof****e in my computer, and have searched for the DLL file of Anti-virus
plugin for Office (including those system or hidden files), I also cannot
find that file.

Does anyone know what's going wrong with my Equation Editor?

Thanks!