I use Windows 8.1

A couple times a week when composing Yahoo email, Yahoo messenger (not the separate Messenger app, but the one that is integrated with Yahoo mail) launches without my wanting it to.

I stay logged out of Messenger, and every time it launches I log out again.

I may be inadvertently hitting some shortcut for launching Messenger, although I haven't IDd the relevant keystroke yet. Messenger usually gets launched during cpu spikes, so it may simply be 'insane' behavior on the part of Messenger.

I realize there is no way to uninstall Messenger, but does anyone know a way of permanently preventing it from launching?

Thanks for any suggestions.