I'm trying to watch a movie I got on a DVD. When I try to play it with Windows Media Player, it says I need a DVD Decoder. When I try to play it with Real Player, nothing happens. I've played many DVDs on this computer before (successfully) without it asking for a DVD Decoder. My friend did reformat my computer a few months ago because it got about 3 viruses (thanks to my brother) and my friend said that the files were too corrupted and it'd be easier to reformat. He made me reinstall drivers(I think?) and such, so maybe I need to reinstall the DVD Decoder I already had (if that's possible)? I don't feel like paying for another copy of something if I already have/had it and could get it back for free.