Do a search for  shelliconcache  and delete it. Reboot.
Windows rebuilds the shelliconcache on reboot. Only takes a minute or two to
try.
Another thing to try is changing the size of the icons. Bring up Display
Properties (rt click on a blank space of the Desktop and choose
Properties)., Effects tab, and put a check in the "Use large icons" box or
uncheck it if it is already checked and then choose Apply. If this works,
you can go back and use the size you prefer.
Otherwise, hang on and someone more knowledgable than I will be along to
help.