SUBJECT: FIREFOX WON'T OPEN. I have used Firefox for years, but upon reinstalling my Vista Home Premium OS, I also had to reinstall all my software. The only problem I had was with Firefox, which appeared to download and install successfully, but refuses to open. I uninstalled and reinstalled it twice from the Internet, but it still won't open from either the desktop icon or the program list under 'Start'. Something seems to be blocking it, but what, and how can I fix this? == This happened == Every time Firefox opened == June 29, 2010 when my Vista OS was reinstalled == == User Agent == Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.5.30729; .NET CLR 3.0.30729)