How to open an avi file?

i downloaded some video game trailor clips and i'm trying to make an amv out of it and cut it and i don't know how to do that, my friend had me download some sort of thing to play all sorts of stuff but it didn't work with the file, and i don't know how to cut it so i can rearrange it in windows movie maker.. it wouldn't load into windows movie maker so what are some programs or whatever i need for this i'm also downloaded some files that are from clips from some movie i'm trying to make a FAKE movie trailor to promote veronica mars the movie because wb pictures has not replied to our petitions, me and some people on twitter you can try and @wbpictures but i doubt they will answer you :(