When I install FF4, the search bar and Firefox (larger) icon appear above the search box, but there is absolutely no text on the screen whatsover. I can type in an entry, and the text in the search box does appear, but when I click the "go to" arrow or press <Enter> nothing happens. The screen is completely static. I tried uninstalling and reinstalling FF4, to no avail...finally, I found 3.6.13 online and reinstalled it, so I can use this browser, but cannot upgrade to 4.0. I have never had this kind of issue when upgrading FF before.