Windows Vista Playing Video
Playing video in Vista, or XP for that matter, requires that you download and install the correct codecs. A codec is a compressor/decompressor program. Whoever produced the film will have used the same codec program to encode the video.
The common files that you will want to play or DIVX or AVI files. You can use gspot or avicodec to detect which codec you need.
http://www.headbands.com/gspot/
http://avicodec.duby.info
I have tended to search google for a "free divx codec pack" and from there I have always managed to get all the codecs I need. If the divx or avi file that you downloaded does not play, or is not recognised, then it is probably corrupted or a time waster! By that, someone has let you download a fake file, possibly a large temperary, and it will not be playable.
If you ever need to install a CODEC with a .ax extension, then you will need to copy the .ax file to c:\windows\system32.
Right Click the .ax file, select properties, click Change (under general tab)
Click Browse, navigate to c:\windows\system32. Select regsvr32, click open and then OK. You can then double click on all .ax files from there on.
Most codecs come with an installer, but beware to virus check, and make sure you are not granting permission to have other "free" software installed, such as MySearch, or other Malware!
SLD Active Codec Selector, fromwww.skynet4ever.tk, will display which codecs you actually have installed.
Sometimes you have most of the DIVX file, or part of it is damaged. Use DivFix "divfix.maxeline.com" to try repairing your file.
It's also worth changing the extension to what it should be. Edit the file with hex or text editor, and you should see some header information. With that search google you might find the extension it should have been, for it to be opened into the correct application.
Must installs for online streaming of video (online viewing video) - make sure they are upto date:
Quicktime
Realplayer
Shockwave Flash
Windows Media Player