It seems that a recent auto-update of some Windows 7 items changed my PC looks. The font of the items in the Start menu looks different and in Windows Explorer, the "arrows" to expand a folder is now a "plus sign". How do I get back to the looks I had prior to this change?
Did you by chance change to a "Windows Classic" or to one of the "Contrast" themes? If so, changing it back to either a "Aero" or "Windows 7 Basic" theme should return the arrows in the navigation pane.