I have downloaded Firefox three times more than a year apart. Each time, I ended up with a virus - the last two times, someone placed some sort of software on my computer that found my admin password (since I don't login with my admin password) and then gave themselves REMOTE ACCESS WITH ABILITY TO CONTROL REMOTELY. I use Kaspersky and Windows updates. I also downloaded Firebug the last two times - all straight from the Mozilla site. This is more than a coincidence. I waited a long time before deciding to download Firefox the last time, but finally gave in so that I could use Firebug. Soon after, my computer began having problems, which I believe was do to background activity from the hacker maxing out my processor. I became suspicious and checked my remote access and saw - as before - that it had been hacked. I'm CERTAIN it's due to Firefox or Firebug. Kaspersky and Windows Defender don't catch this virus/Trojan even after a full scan. Someone needs to go through the code and find out how this is happening.