For all of you who are having trouble with codecs, either not being able to play a movie you've downloaded or not having any sound/picture, this guide should help you.
The Easy Quick-Fix Method
For the lazy people amoung you who want the simplest possible solution, may I present Video LAN Player (VLC), it's a good video/audio player and comes with all the codecs you will need (at least, all the ones you will likely meet in your p2p travels) and has many features making it my player of choice.



