Make the background transparent for icons :Generally the background of icons is transparent by some way it turns into some colour this will not be nice to look at isnt it ??
So try these,
1)right click on the desktop>arrange icons by>lock web items on desktop (uncheck it)
If this does not solve ur problem then try
2)Go to Control Panel>System>Advanced>Performance area>Settings button>Visual Effects tab "Use drop shadows for icon labels on the Desktop".(check it or tick on it)
this will solve the problem