Hrm... I use it on what systems I have windows installed on (perhaps not IE6) and unless im am wildly mistaken everyone technically does considering it is not only a browser but an intergrated part of the operating system that allows for file exploration. Sure that does not mean you are using it to browse the internet but by all technical rights (which you can even use it to track your history of what files and folders youve opened in your system the same way you would track browser bookmarks) a LOT more people use it than realize or would even be willing to admit.
Edit: More to the point, Open up task manager, then to processes tab, then "end" Explorer.exe or iexplorer.exe and see what your windows based OS thinks of you trying to stop using IEX
Edit: More to the point, Open up task manager, then to processes tab, then "end" Explorer.exe or iexplorer.exe and see what your windows based OS thinks of you trying to stop using IEX