BerniceC: Hopefully someone will jump on here to help better then me - I'm thinking for some movies, you need special codec's loaded to properly view movies. I had to load a lot a long time ago, and since then I have no problem playing just about any more - but I'm pretty sure it's because I loaded all the codec's that I needed.

Now I'm not 100% sure about this - but you may want to get this: http://www.free-codecs.com/download/K_Lite_Codec_Pack.htm

It's a pack with all of the most popular codec's on it - and says it will allow 99% of movies to play correctly. Again, not 100% sure about this so please don't get mad at me if this blows up your computer or something.