In case you are facing unable to play the file format like unable to play .avi file, .mkv file or any other file format then VLC player is the solution for you. VLC media player is the ultimate player that will play most of the file formats without any codec
About VLC Media Player in their own words :
VLC is a free and open source cross-platform multimedia player and framework that plays most multimedia files as well as DVD, Audio CD, VCD, and various streaming protocols.Its Simple, Powerful and Fast.Plays everything, Files, Discs (DVD, CD, VCD), Devices and Streams.Plays most codecs with no codec packs needed .To know more features of VLC player just visit the link below
It works on Windows, Linux, Mac, Unix and Android as well...
You can download VLC player from the link below and moreover its free
If you need more skins for the player you can download from :
So now you got the universal player for all kind of video and audio formats but if there is a specific player that you like to use and it can't play the video file then? Here is the solution, which is K-Lite Codec Pack and its absolutely free that you can download from:
About K-Lite Codec Pack in their own words :
K-Lite Codec Pack is a collection of codecs and related tools. Codecs are required to encode and/or decode (play) audio and video. The K-Lite Codec Pack is designed as a user-friendly solution for playing all your movie files. With the K-Lite Codec Pack you should be able to play 99% of all the movies that you download from the internet.
There are three versions of K-Lite basic,standard and full depending upon your need you can download the required version,to see the difference just visit the official page
Incase you use Windows Media Player as your main player dont forget to select the option select all video and audio on the screen where it says choose the file extensions that you would like to play with Windows Media Player
Its recommended to download and install the K-Lite Codec Pack Full version so that you have the full range of codecs.Now once you have VLC media player and the K-Lite codec pack you shouldnt face any problem in playing any audio/video format and you will be able to play your files in your favorite player as well.