After KMPlayer's demise (followed by apparent death and recently, rebirth as undesirable bloatware), Potplayer has taken its place. It's the KMPlayer that should have been but never quite was. Currently, it is probably the best all-round player for Windows, despite the lack of documentation combined with an overwhelming array of options. Less tech savy users can just keep default settings without getting confused by too many options and will find PotPlayer suiting their needs as well. Plays just about anything, so no need of manually installing codecs, except perhaps in very rare instances where unusual formats have been downloaded. If I was asked to recommend just one player, Potplayer would be it (though others like SMPlayer, GOM and, well, for those that like it, even VLC, are also worth having a look at. I prefer to have several players as fall-back options. Not installed but for this purpose ideal are portable versions can be copied to any folder on any disk, including portable drives that can be used on other computers away from home).