DVD Decoders on Win 98 please

I have a DVD Rom drive on my laptop but it won't play movies. I'm told I need a DVD decoder for this. Is there anywhere I can download one for free? Please.

Out of the listings in under three minutes. ttt.

the whole bit torrent thing confuses me. I have about every possible toy I can use computer wise, but my non computer mind just cant seem to figure out step by step way to downlaod and watch these bit torrent events. help?