Best free video editing software download?

i use wmm for my videos, but it stopps working everytime i try to publish it. i need something new, something thats free, good, better, anything that can also add subtitles to the video and drop wav's and videos, sound effects onto. please give some links for something that i can rely on. i need it so i dont lose subscribers in youtube. cause i cant submit a video knowing about those parts i dont want in it.