Where has all this come from?

Hello r/techsupport

I was looking to clean up my drives and found this huge dump of what seems to be movies. I tried opening some files, but all don't work. I have not downloaded any of these, and no one else uses my computer. I've taken a screenshot, which includes the file location, and the Scanner view. The files I'm taking about are the purple section.

http://i.imgur.com/tLxt9.png

If anyone has any sort of idea, please help me out! No idea where they've all come from.

Thanks

P.S. All files are .avi files of movies, but all don't work with anything, even vlc.

EDIT - Folder says it includes 413GB of files, but my drive is only 240?