What happens if I reinstall iTunes?

Whenever I try to open iTunes it gives me this error message: "iTunes cannot run because some of its required files are missing. Please reinstall iTunes." I have absolutely no idea what file is missing, nor do I know how to figure it out. So if I do reinstall it, won't my library be wiped clean? I have a lot of music that isn't on my phone, as well as movies and music videos. Please help!