i have used in the past a codec pack called k-lite mega codec pack which enables your computer to play most video files. it also comes with its own basic player, media player classic for playing video files. it is available to download from the link below.
http://download.cnet.com/K-Lite-Mega-Codec-Pack/3000-13632_4-10794603.html?tag=mncol
or, you can use the following program, quick media converter to convert the video files to other file types.
http://www.softpedia.com/get/Multimedia/Video/Encoders-Converter-DIVX-Related/Quick-Media-Converter.shtml
hope this helps