All the Icons and Programs on my computer open up iTunes

My sister was fooling around with my computer about 2 months ago when this orignally happened. When it happened then I unistalled iTunes and just dealt with not having it BUT now I've gotten a new iPod for christmas and would like to be able to have music on it, so I re-installed it and the exact same thing happened.

All of my desktop and Toolbar icons have changed to iTunes (excluding Skype?? don't know why) and when I hover over them they still say their actual program name, but clicking them opens iTunes. I have Windows 7 and just updated a little while ago.