Explorer crashes when a folder is closed

Whenever I close a window on my computer I get a pop-up telling me there's been an error and Windows Explorer needs to close.
When I got it I thought this was a problem with my hard drive being too full as I had it almost packed working on a movie with some friends however I recently finished it and deleted off most of the raw footage clearing out a lot of space and have found the problem still persists.
I don't know if this is a related issue but I get the same thing when I close an Internet Explorer window as well although I don't use IE so that never bothered me.
Can anyone please help me? This is extremely annoying.