Help! I can't fix or uninstall/reinstall iTunes without getting this error message: "The path \C\Users\(my name)\AppData\Local\Apple\Apple Software Update\iTunes64msi.' cannot be found." So I can't remove iTunes.

Here's the complete message:

"The path \C\Users\(my name)\AppData\Local\Apple\Apple Software Update\iTunes64msi.' cannot be found. Verify that you have access to this location and try again, or try to find the installation package 'iTunes64.msi' in a folder in which you can uninstall the product from iTunes."

So I'm stuck in this loop in which I can't download an update, can't remove iTunes to reinstall, and can't use iTunes currently as it shuts down at the drop of a hat. Am I hopeless or is there a fix I can find?