^^ You can? But its a Trial, right? It costs like 30 Euros in Germany...
Anyway, if you would have done a search, only in the technology subforum, you would have found 3 threads or even more, telling you that VLC (video lan client) plays just about everything, because it has built in codecs...
Or, you could get something like BSplayer, which I mostly use, or simply the media player classic.
But you should be aware, that not the player actually shows you the video, filters and codecs do, so make sure you got a good codec pack (really, just search...) or gt ffdshow, which is a nice filter that will play most h.263 and h.264 stuff... I think...
Buba