im not entirely sure sorry but from your description im guessing its maybe the desktop shortcut toolbar.which can be handy if placed on the taskbar. are there any links to porn etc or is it just your desktop icons mirrored? if the latter then this is more than likely what it is.
try right clicking the displayed toolbar and select toolbars then untick 'desktop' if ticked.
alternativily drag it down to the taskbar at the bottom of the screen and right click it again and select 'lock the taskbar' to keep it there. now when browsing you can select items from the desktop without minimising the web page to get to them etc.
if this is not what it is then try running adaware and spybot to check for spyware nasties maybe click here click here