for some reason I always automatically type my search entries into the navigation bar rather than the search bar. It used to default to google search, now it defaults to yahoo search, which I hate. I cannot figure out how to change the search engine that the navigation bar uses! (I know how to change the one the search bar uses)
Start Firefox in Troubleshoot Firefox issues using Safe Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance/Themes).
Don't make any changes on the Safe mode start window.