Can't find the iTunes.msi file anywhere!

I'm trying to upgraded my iTunes so I can basically have my life back. When I go to install the upgrade, i get a message saying that it can't uninstall the older version of iTunes or QuickTime and they need to be uninstalled so the upgrade can be installed. So I try to uninstall the iTunes through the Control Panel and it can't because it can't find the "msi" file to uninstall the iTunes. I've researched it in this forum and found a post with a similar problem. BUT, after trying to install the Windows Installation Cleanup Utility 3.0, it turns out that I already have it installed on my computer. So I'm stuck! I need to know where the iTunes.msi file is so I can go forward. Can you please help me!?!