help from computer people

[DierwulfBL]

ok here's my ordeal, i refuse to put the evil viruses of realplayer and quicktime and all those other viruslike "media playing" things on my computer so what im looking for is a codec (dont know if youd call it that) or program that lets media player play all those weird file extensions that are common with realplayer/quicktime. I know theres a thing like that for media player just hopin someone could steer me the right way towards a good one/one in general cause i cant seem to find it. I'm sure other people would be interested in getting those viruses off their computers too so it shall benefit all, thanks.