i use GOM-player to play VIDEO files in my XP OS it PLAYS most of the video files but sometimes it tells me "You do not have the necessary CODEC required to play this file" can some one tell me what do you MEAN by this??? what i should do for this!!! thankz in ADVANCE!!!! Try using VLC Media Player: http://www.videolan.org/vlc/And/or do a search for the KLite codec packs....