I operate windows 7 I have upgraded firefox from 3.6 to 4 since downloading onto my pc I am unable to surf the web..all of my emails operate and all of my bookmarks work as well. As soon as I type a word or part of a word into search pane (google) it stops, some web pages are displayed but as soon as I click onto one the system freezes and says firefox is not responding. I have to close down ..Any one help pse ?