iTunes Automatically Restarts like a VIRUS!

How do I stop this?

iTunes re-opens itself repeatedly, every time I close it. Even after going through task manager and manually ending all apple services, and removed everything from startup, iTunes STILL opens and reopens immediately after closing. It seems to be triggered by file explorer. Whenever I browse, or even just select the iTunes folder, the virus-like behavior begins. It will not cease until I restart the computer, and as soon as I open file explorer again, same problem. Avoiding file explorer is not an acceptable resolution, nor is avoiding the iTunes folder. I must use iTunes to sync my ancient iPod, so uninstall is not an option either. Any ideas?

So that brought me here. Upon logging in, I was asked to create a username. I typed my username and the page got stuck in an endless cycle of "Cannot create username. Please check the form below." - form below - "Please select the Check Username button before proceeding." -- I did so, agreed to terms, and clicked proceed, only to continually be brought back to the same page. Tried this process on several browsers. Finally, changing my (unchangeable) desired username to abcdefg, allowed me to advance. I need this changed as well.

Thanks in advance...