Video codecs are most likely the issue at hand...
Hi nice to meet you, the names Remdawg Remmy.
OK now that thats out of the way....
Go to the download page up top and download ffdshow, or be an idiot like I was and Google search the K-Lite pack. (I say that because someone recommended it to me, but I haven't quite figured it out yet.) Once you have those configured, your videos should be good to go.
Happy Playing!
-Rem