I opened the Facebook app once, and now it set itself to "autostart" so that every time i turn off my phone (something i must do often) and then turn it back on, it runs the application. i don't need it now and it's just making me pay for the internet, because i don't always remember it's on.

i went to the settings, but i can't change anything because all the applications that come with the phone are locked. is there anything i can do?