It might depend on what type of video's you want to play, but I think you're more in need of a better PC than a better player.
I have an HP Pavilion running millenium. Processer is 633Mh and ram is 192Mb. I want to know if there is a media player I can run that has cleaner videos than the Windows media player 9 (can't get higher than 9) and still have the repeat and full screen function. Thank you