Have you noticed in vista, if you try to rename a file, it will only highlight the name and not its extension. You have to drag the whole thing and rename it with the extension you want and of course it’ll give you a warning that you are trying to alter the type

In XP, once you right click and choose rename, it’ll highlight the whole thing

I usually use this method when creating batch files and start off with text documents and then rename it to .bat to run it

You have the option to display the extension of the file or not, to have it as “memo.doc” or “memo”

In XP and Vista: Go to Control Panel -> Folder Option -> View