Computer is an HP Envy 17 laptop. Firefox does not appear on Task Manager list of processes or applications. System restore did not fix problem. Google Chrome works ok. Internet Explorer works ok until I try to download Firefox. Then it too crashes. This pc has been running Firefox fine since I purchased it 10 months ago. I upgraded FF3 to 4 then to 5 with no problems. Suddenly yesterday it stopped working. There is no error message and evidently FF does not launch because there is no listing of Firefox in Task Manager processes or applications. I tried uninstalling Firefox, then tried to download it usingInternet Explorer, but when I click on the download button at the Mozilla site, Internet Explorer crashes. I did a system restore to 8/16/11 when Firefox was still working. This restored the program but it still does not run. Google Chrome seems to run fine. My internet access is via wifi through an Actiontec router and Verizon Fios. I am running Symantec Endpoint virus protection and do not have any Norton or Skype programs listed in Control Panel. My pc is set for automatic updates from Microsoft and from HP. They both say my software is up to date. Is there a fix for this problem or is it a sinister plot by Microsoft to force us to use Internet Explorer?