After a while, no icons in Explorer, and right-click hangs the window

Hello, Well, the title is pretty much self-explanatory. I use 8 Pro Build 9200. When I boot, everything is normal. Then, after a while, usually a dozen minutes, whenever I open a folder in Explorer, no file icons will be shown, whatever the file type : I only get a blank generic rectangle instead of the proprer icon. When this happens, I can be totally sure that any right-clicking on a...