You know, I sometimes see some mini-videoclips that some users made to decorate their threads, but I don't know how to make them. Can someone help me, please? Thank you.

No, not videoclips, you are talking about gifs ^^ Gifs can be found on various site in the internet, like gifbin.com for example. It's possible to create a gif from a video, one site i know is gifsoup.com. You can also do it with various programs, but gifsoup is one of the easiest ways to make a gif.

And can you make one with Windows Media Maker?

I really don't know, I'm sorry. Maybe you can google it and see if you find something though, if it's possible I'm sure someone had posted HOW somewhere xD

OK, thank you.