can you explain better? Is it that differnt file types open in a differnt player and not one? If you want all files to be played in one player on windows XP go to start>Control Panel then click on Add/Remove program then on the left click Set Program access and defualts then there should be three things

Microsft windows
Non-Microsoft
Custom

check custom and expand it were it says choose a defualt media player: check witch ever one you want to use