How to Start Firefox without session restore

I have session restore enabled. Normally I love it. But I accidentally navigated to a malware site. It is trying to download some malware onto my computer and I can prevent it. But I can't navigate away from the window or close it because it pops up a window to prevent me from leaving. I don't dare click cancle in it because I understand clicking anything in a pop-up window give it some permissions. If I click the red close button onthe upper right another pop up just shows up.
The only way I know to get rid of the thing is to kill Firefox with the task manager. BUT when I open Firefox again it just opens the malware site again because of Session Restore.
Does anyone know how to open Firefox while preventing Session Restore?
Thanks,
Chas

 

Hurray , Saved by safe mode. Whien I stared in Safe mode the window poped up to give me the choice of a new session or a restore. I choose new. And then next time I opened Firefox regular the malware session didn't open.