In earlier versions of Windows, all one had to do to change a file type is simply rename the extension. How, though, does one change a file's type in Windows XP? For example, I have some downloaded video files that are listed as "htm" files. When opening them in Windows Media Player, I get a message saying that WMP might not recognize the file type. Ignoring the message, I ask WMP to play the file and it does so PERFECTLY (in other words, the media file has a wrong extension). I want to edit this file in Windows Movie Maker, but it "doesn't recognize the extension" (it doesn't even try to, unlike WMP). In earlier versions of Windows, all one had to was to rename the file's extension (from .htm to .wmv). But HOW can I accomplish this in Windows XP?