Thanks for the replies
Wish it was that easy Birdy, but AC3 would have worked on the first try. It's really strange easterhay that there would be no way of playing that format on Windows, because the person I got them from uses Windows as well. The only problem is that I can't get hold of him at the moment. I am pretty sure that he wouldn't have any files that he couldn't play.
He uses Mplayer a lot. Maybe there is some kind of plugin for it. I'll just have to wait for him to get back. Might be a good idea go give the address to other people that have problems playing video. Pretty sure it beats VLC anyday. And the best thing is that you can sync sound and subs + change settings for color light saturation etc. Get it here
http://www.mplayerhq.com