ive downloaded divx and the avicodecpack but still it wont work. The movie starts then the screen freezes but the sound continues. Is there something i need to do with the above downloads to make them work? Or is there something else i still need to download to get these files working?

Try the free VLC media player, which comes with built in codecs and can play almost all files without any problem.....:
http://www.videolan.org/vlc/
If that player can play the file then you have most likely a corrupted file.
Alternatively you can download the k-lite codecs pack which includes the G-Spot progam. This will be able to show you what codec this specific file used for encoding and also whether you have the codecs installed on your system or not. It also has the Media Player Classic included, which I believe is the second best player right after the VLC-player:
http://www.k-litecodecpack.com/

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