Okay, here's the situation: For awhile, I've been an otaku, and have downloaded series I particularly enjoy so I can go back and revisit them at will. However, more recently, I've wanted to try making some AMVs on Movie Maker. Unfortunately, because all of my files are in Real format, MM won't recognize any of my downloads. What software could I use to convert my files to a recognizable type? Or, is it possible for WMP and MM to be made to recognize it?

Forgive me if this question has been asked before, but I'd really like to avoid downloading from another site all over again.