crewmeal:
You should be able to control what apps open when you log in.
Go to the Apple menu, top left, choose "System Preferences", then select "Accounts." Click on your login name - if necessary clicking the padlock bottom left on the Preferences Pane first - and putting in your password. Then select the "Login Items" tab, and you can remove / disable apps which get started when you log in.
See also
How to Turn Off Startup Programs on Your Mac (OS X) for more info.