For Kenpu... DiVX/xViD/MKV/MP4/AVI video playback

Video LAN Player:
http://www.videolan.org/vlc/

Now, if you encounter problems there, go here:
http://www.cccp-project.net/

Install it then restart PC. (Install just Media Player Classic, not the other media player as it tends to have issues.)

For Xvid: http://www.xvidmovies.com/codec/
(In case you run into problems using CCCP codec pack above.)

For Divx: http://www.divx.com
(If you want to use this instead of ffdshow codec in CCCP isn't working right.)

I also have Core AVC/MP4 HD codec on me if needed, but if you have a high-end machine to handle it. XD

- Ase