I downloaded and installed firefox 4 several weeks ago. I noticed a day or so ago that when I clicked on firefox on my desktop, it "reloaded" firefox 4, giving me the welcome notice and the "getting to know your browser" page (http://www.mozilla.com/en-US/firefox/4.0.1/whatsnew/) all over again, although I had not reinstalled anything. Tonight when I try to open firefox, it continually generates windows (more than 50 in seconds), and I have to use task manager or a reboot to get it to stop. I ran avast! and found 2 files on my guest account that were win32:malob[crypt]. Those have been isolated, the guest account deactivated, the temp folder in the C:\users\guest\appdata\local folder (where the 2 virus lines were found) has been deleted. Still, the firefox on my main admin account is continually generating windows. I can, however, log on to firefox using another user account on the same computer without any problems. Not sure if it matters, but the troubleshooting information is, of course, taken from the user account that isn't having problems. Any thoughts on what is going on? Thanks for your help!