Ok, Floyd, open a Explorer window. May as well be My Computer, on your desktop. Up the top menu choose View >> Folder Options, and choose the third tag along at the top, Which is labelled ‘File Types’.
Click on one, and choose the Edit button. This brings upa semi-complicated Window that will probably stump you, and make you want to learn how to use Linux.
Although, if Linux isn’t your thing, play aroud with the settings in that window. You can also add files that aren’t already associated, and do neat things like add extra actions to a particular file type. For example, I have 3 different Edit actions for HTML files, and an Open in Internet Explorer action as well.