i d/led a couple of dif movies a while ago and each one only played up until a certain spot like 4 mins and some-seconds. Why do they do this? is there a different media player that i should use besides windows media player or what is the problem?

I only can guess, because I'm a newbie in Gnutella, too. But it seems, that you try to download files from persons, who had not finished the download for themselves. Should mean: you just downloaded the first part of a movie and that's why your player only plays the beginning.