Hmmm... I am not sure the Quickbooks employee answer solves your problem, as it will come back next time.
It sounds like you want to either uninstall QB completely, or at least stop it from autostart when the computer boots.
Uninstall is from your apps menus (right click on windows icon at bottom left of screen)
Change or disable programmes from startup is in Task Manager (Windows+R then type taskmgr)
Choose Startup folder and disable those that you do not want running in the background.
