Firefox not responding

  Hi guys. I use Firefox and opera. Opera works great until now but Firefox keeps blocking and it it shows program not responding.
Before i write mails(or posts..ha ha ha..) with words that only i understand on their forums i want to ask toms community if is there a way to fix this?
I am getting close to my limit now because i get lots of "program not responding".  
Or is there anything else that can disturb the browser?

I do not want to reinstall it because i have too many passwords and bookmarks saved.  

Thank you for your time spent reading this and for the possible help you can give me.