If you find that a video won't play properly, or you're just in the market for a new media player, then you should check out VLC Media Player 2.0.4. This free software will work on any Windows system, from XP to 7, and it enables you to play nearly any type of media file, and tweak a lot of settings if you feel the need.
The installation process doesn't take too long and it appears that VLC has updated their interface quite a bit. I've used it for years, but haven't upgraded until now and they went from a small, really basic-looking interface to a slightly smoother looking interface with a media window that's always visible. But I've always liked how, with this player, you could be almost sure that your files were going to play correctly; they seem to support all of the different file formats out there.
Plus you could change a lot of settings, to improve your viewer experience, like adding in subtitles, changing the brightness, watching in slow motion and so on. And they made a few of the options easier to access, with icons right below the progress bar, plus you can even have multiple instances of this player open at once. Sure, this isn't the flashiest piece of software you'll get your hands on, but you can be sure that your files will play correctly through this software. I mean, you can use subtitle files with this software, if you tell it where to look for them, and it plays MOV files a lot smoother than even QuickTime will.
So, if you have a file that doesn't want to play correctly, aren't sure how to get your subtitles to show up or you just want a new media player then you should definitely look into the VLC media player. It's easy to use, it works for almost all files and you have a lot of settings you can change with it.