We use the Adobe Flash player for playing streaming videos through YouTube, if you can't see the Flash player at all or can't use it you can choose to install the latest Adobe Flash player. You can download it here from the Adobe website.
To play DivX, XviD (AVI) you first need to install the DivX codecs or the XviD Codecs. Then you should be able to play the video with Windows Media Player. It's also possible that you need to install some other video or audio codecs such as AC3 audio, OGG audio or some other, read here below how to identify what audio and video codecs you need. Or use VLC Media Player / Videolan and you don't need to install any codecs cause they are included.
Play DivX with Quicktime DivX codecs either from divx.com or from 3ivx.com (version 4.0 PR, slightly faster than divx.com codec). Both are available for OS9 and OSX.** There is a bug in the AVI file format which results in Quicktime not playing correctly MP3 sound in a DivX movie. To correct this problem, run your DivX files into Divx Doctor II first.
Play with MPlayer or xine or VLC Media Player / Videolan.
Problem playing DivX,AVI,XviD:
Use AVIcodec or Gspot to identify what video and codecs you need to install if you have problem playing the video. If you still have problem try then to "fix" the DivX, beceause the DivX can have been broken while you downloaded it, read here how to fix a DivX/AVI.
Videohelp.com has a great guide for this available at their website.
You can burn DivX videos as data DVD's, nearly all standalone DVD players these days can play DivX material. You can also choose to convert it with, for example, Imtoo's DivX to DVD converter.
In Windows Media Player go to View->Options, then turn off the Hardware accelaration(under Playback) by moving the slider to None. Now play the video and press the PrtScn button (above the Insert button on your keyboard) to take the screenshot, last launch your favorite photo editor (the easiest way is Paint) and paste (ctrl + V) to get the screenshot.
Download Hypersnap DX. Before capturing select in Hypersnap under Capture->Enable Special Capture DirectX Overlay. Then you just start windows media player and play the video or use any dvd/divx/vcd software player and forward to the screen you want and hit pause. Now start Hypersnap DX and select Capture->Window,Button,Control and click on the video window and you will get the image.
Screenshot from DVD: Use WinDVD and play the DVD and just press P on your keyboard and a screenshot will be saved under the folder Capture where you installed WinDVD(usually c:\program files\windvd).