Un-install old WLM before installing new?

I have had some advice to un-install windows live mail before installing new versions. I know it works to install over the top. What is the correct way to do an upgrade of windows live mail? I'm know both work but what is the best or correct way?

If we're supposed to uninstall Windows Live Mail before installing the new version, how are we supposed to get access/permission to do it? That’s the exact problem I’m having in trying to uninstall Windows Live Mail. Here’s a copy of what I posted:

“Vista won’t give me access to uninstall Windows Live Mail!

I’m using IE8-RC1, which is working perfectly, except ironically, the only application it seems to be in conflict with is Windows Live Mail. I tried the “compatibility mode” option which didn’t help, (even added Windows Live Mail to the list of apps to always run in compatibility mode), so I thought I would uninstall it and reinstall it – hoping the new download would solve the problem. However. . . Vista won’t give me access to uninstall Windows Live Mail. When I right click on it there’s no prompt to run as administrator, and I’ve already turned off UAC. Does anyone have a solution?”

I think it's bad advice. The Windows Live programs I have in "programs and features" are cryptic. The closest one to Live Mail is "Windows Live essentials". I don't think I will even try it. If anyone has some advice...let me know.