Change "Startup" to "Show a blank page" in Startup, home page, tabs, and download settings

Yes, I did this, of course, but FF still loads the previous pages anyway... I also set the home page to a blank page but that didn't help either. Any ideas?

Make sure that you close Firefox properly, otherwise session restore will try to open the tabs and windows from the previous session.
See Hang at exit:

• http://kb.mozillazine.org/Firefox_hangs
• Firefox hangs or is not responding - How to fix

Set the pref browser.sessionstore.max_resumed_crashes to 0 on the about:config page to get the about:sessionrestore page immediately with the first restart after a crash has occurred or the Task Manager was used to close Firefox.

See:

• http://kb.mozillazine.org/Session_Restore#Restoring_a_session_after_a_crash

This is a really annoying "feature" (hah!) of the new Firefox. It means that I have to remember to close all other tabs, then go to my blank home page, before closing the window. That way if my roommate uses my computer next she won't see what i was doing.

Yes, i know she could poke around and find out in other ways, that's still no excuse for Mozilla to give her the option in one click, practically begging her to click the big "restore previous session" button in the middle of the screen.