"iTunes Cannot Run Because Some Of Its Required Files Are Missing. Please Reinstall ITunes"

I use iTunes on my Windows 7 computer to sync with my iPhone, and the last time I went to open iTunes it gave me the error message "iTunes cannot run because some of its required files are missing. Please reinstall iTunes."I had heard that if I uninstalled Quicktime (which is bundled with iTunes when that is downloaded), then reinstalled it separately, it would work again, but after trying that it didn't. So I decided to just uninstall iTunes, then reinstall it. However, every time I try to uninstall it in Add/Remove Programs, it just sits there saying it'll be about eight more seconds to go to finish deleting, but it just sits, and sits, and sits...... Nothing. I also tried to just install the newest iTunes on top of the existing one, but every time I try it tells me that it's already installed and to click "Ok." So I can't uninstall it, nor can I install it, nor will iTunes open on its own. I had done a system restore recently, so I don't know if that had anything to do with it.