Unable to open Itunes

Hi... I've been looking through the different questions and haven't found some with the exact problem, some are similar but not the same. Anywho, when I initially installed Itunes on my Lenovo, it worked great for like 3 days, I used the Genius application, and everything seemed fine, then I attempted to log back onto my Itunes recently and have been unable to since an error message appears and says - "the itunes application could not be opened. the required folder cannot be found." The itunes folder is still on my computer, and everything seems to be there. Also, I've looked at taking out the bonjour service to see if that causes the disruption. I need help please. I've also tried to uninstall my itunes and I keep getting an error message telling my that it cannot locate a folder.

Thanks to anyone that can assist.