My previous version of Firefox (6 ?) would not open ... I kept getting error boxes saying something about an illegal application (sorry, didn't write down the whole message). When I opened IE, it would only let me open 2-3 tabs before giving me the "IE has experienced some problem and has to shut down". Once I got the Mozilla page open, IE would shut down anytime I tried to download Firefox. I finally (after more than a couple of dozen attempts) got the Mozzila page on, clicked the 'download' button for Firefox 7, and then actually got the set-up EXE file saved in my Program files. The first two times I tried to open my 'new' firefox, I got the same "illegal application" error. I would uninstall and try to down load again ... I finally "got a keeper", but then discovered I had lost bookmarks, add-ons, extensions.