This happened nine years ago. My computer got taken over. Stitched up like a kipper.
What happened, was I accessed theregister.com, a tech news site run by some good people who are UK-based. I read it pretty much every day, as a good way to keep up with what's going on.
So, one day, I went to the Reg to read the news, using my Windows 98 computer (which tells you something about how long ago this was) and bish-bash-bosh, as soon as I accessed the page, lots of things happened, and my computer told me that there was a problem. I don't recall the exact message, but I seem to remember that the gist of it was that I needed to spend £40 on some software to deal with this problem. Like hell I will! It's not that I would refrain from forking out £40 for something useful, it's that my first thought was, they're trying to sell me something that is probably malware, to get rid of the malware they just saddled me with?
It turned out to be an iframe exploit that did the installation of the nasty, and it came not from the Reg itself, but from the adverts on the site, which are hosted by an advertising company. Bottom line - this was a perfectly serious and respectable site, and I got stitched up like a kipper.
I spent half an hour trying to get rid of it by deleting stuff, but it kept coming back. I suppose I could have done a proper analysis of what was going on, but reverse engineering stuff like this can be very time comsuming, and I decided it wasn't worth the effort in order to clean up just one computer. Because there was another way. I zapped the hard drive. That means, not just formatting it, it means writing zeroes on every sector, so that you're starting with a really clean slate (formatting doesn't do anything to the partition sector). My idea was, reinstall Windows 98. But after I'd finished the zap, I thought, hang on, wouldn't this be a good time to start using Linux as my every-day workstation for browsing, emailing and so on?
By 2004, I'd been using Linux on servers for several years, and I knew my way around it. I also knew that there was a graphical user interface I could use, but I'd never really tried it seriously.
So I installed Red Hat Fedora, whatever was the latest version in 2004. And I found that pretty much everything I needed was included in the (free) install. And that the user interface (Gnome) was enough like Windows that I already knew how to use it. Even today, I run a Windows box for just three things - Memory Map, GSAK and iTunes. I don't access web sites from a Windows box now.
And for the last nine years, I've not had a problem.