Double icon images on desktop

I'm running Vista Home Premium on a Gateway GT5476E computer. Up to now,
everything has been fine. However, recently I noticed that some of the icons
that show on the Aero desktop often show full or partial copies/images of the
shortcut icons, adjacent to the real icon. This can be corrected by a refresh.

I have been installing a few image manager programs lately, like XNView,
Fast Stone, etc., and at one point I changed the refresh rate on the monitor
to 75 Hz from 60 Hz. When I changed it back, it was still happening.

Not a terrible problem, but annoying and, possibly, a sign of something worse?

Any ideas?
--
Larry