I tried a lot of things that didn't help. Gave up and went back to Firefox 3.6.15. For me, at least, Firefox 4.0 wasn't obviously faster. Also, in the older Firefox there was a down arrow beside the "go back one page/forward one page" buttons that dropped down previous web pages. In 4.0 it seems to be gone. You have to right click on the buttons to get a drop down list. Not a big thing, just an annoyance. Honestly, using the .0 version of any software package is somewhat masochistic. Note that you can use the down arrow and enter keys to search from the Google search bar drop down in Firefox 4.0. You just can't do it with the mouse.