" Frankly speaking, you went somewhere you were not supposed to go, or did something you shouldn't have done. " Wrong. I get pop-ups a lot of commercial sites, not warez, not porn sites, etc. (Well, I did before I got Firefox.) As well, if you type in a URL just slightly wrong (there are a lot of jerks who mimic popular site names and deliberately misspell the name to get people who meant to go to the real site) - or if the site was abandoned and some scumbag picked it up, you may get hit with all sorts of garbage as well. I tried to direct someone to a legit site last week, and they were innundated with ads because they missed a letter in the URL when they typed it in. We cleaned out over 700 spyware bugs in his system by the time we were done. (2 hours on the phone fixing it. Ick!) Some browser hijacks will allow you to change the homepage back for that session, but they modify the registry so the next time you start your computer, the home page is hijacked again. There are ways to find the bug that's causing a browser to be hijacked like that, but there's not enough info here to figure it out. The last time I checked Firefox was safer than IE due to the way IE handles things like ActiveX.