Note: Windows Movie Maker 6.0 from Vista was the last version that included the "Film Age" effects. The effects included desaturation, flickering, vertical scratches, film grain and other visual artifacts that made your video look older.
In the latest version of Movie Maker, the most you can do is apply a Black & White or Sepia effect as noted previously. Alternatively you could load WMM 6.0, use it to "age" your video clip, save it as a movie and then make further edits back in the latest Movie Maker.