BT browser is built on Internet explorer. I don't think there are any serious modifications done to it other than branding, but I'm unsure. Most likely BT is affected in the same way that IE is - the trojan will be automatically downloaded without your consent. I'd be very surprised if the yahoo people had modified the browser to the extent that they changed the way it handled files, but it's possible. dwarfie76: As I understand it, the exploit isn't "directed" at Firefox, it's directed at Windows and Internet Explorer. Because Firefox runs on windows and allows people to access the internet, the file can be downloaded using Firefox. It "affects" Firefox in the same way that it affects any other program that accesses the web on widnows: Opera, bittorrent, and many others.