(of course if adblocks is not loaded, you will not have that option)
You could also take a look at this which talks about what to do if Firefox stops working correctly. (I have not read it all yet, but hopefully it can help)
BIG BAD WOLF:
I tried everything on that web page to no avail. I just saved my bookmarks and reinstalled Firefox. Everything is working again, juts wids I knew what the problem was so I could avoid it in the future.