Stop Outlook XP autostart at boot

Does anyone no how to stop Outlook XP from autostarting at windows boot? I have looked in all startup folders and there is no shortcut to be found. The owner of the PC says they changed a setting in Outlook that caused this, but they cannot remember where the setting was located. I have looked everywhere for it and its dring me nuts! It slows the boot process and makes it a pain when working on the PC. Thanks in advance 🙂