Have you tried downloading vlc and playing then in that as I have seen a problem before caused by a codec update for MS media player cause the same damage, also I,m not aware of any such virus on this or any other p2p network at this time, if you could provide a list of your files and their hashes we can track the files themselves on the network and test them
Go here for VLC
http://www.videolan.org/vlc/Get this tool to hash the affected video files if vlc is also unable to play them
httpss://archive.winmxworld.com/Greyproc/MXHashish_V1.0%20-%20230405.zip
Use this tool to generate hashes for the afflicted files and posts them to me on this sites PM system for us to check the srcs on the network are fine or not whatever the case may be.