CANNOT DOWNLOAD ITUNES. PROBLEM WITH FILE NAME? 10 POINTS BEST ANSWER!!?

hai i really need some help please! i cannot download itunes because i keep getting an error message that says this file name already exists and im given an option of either renaming the file or replacing it. ive searched on my computer EVERYWHERE and i cannot find this "file" at all! it gives me a directory address but i still do not know where to look for it. PLEASE HELP ME! i am really desperate lol