Can't create new folder

As of a few hours ago, I can no longer create new folders on my computer. It's a custom built computer and everything was running fine, norton found no harmful files when I ran a full scan, and I haven't downloaded anything fishy (all I've dl'ed were a few steam games, winrar, and some programs.) The problem started in the middle of the norton scan and a steam download.

 

This is pretty annoying, anyone have any idea how to fix this?

Norton is awfull.

Try doing this http://www.howtogeek.com/howto/windows-vista/add-take-ownership-to-explorer-right-click-menu-in-vista/ and taking ownership of whatever folder you are trying to make a new folder in.