What software can I download to watch video files on my computer?

I got a new Lenovo computer and it did not come with any software that allows me to watch video files I download. What's a good media player I can download?

It should have one called Windows Media player.

If not, you can try VLC. It's completely free; http://www.videolan.org/vlc/index.html

Just look up video player for pc.