I am playing an on-line game out of Germany called Tibia. There is another thread about it here. There are a lot of hackers playing this game and visiting any of the fan-sites is likely to lead to some kind of infection. I don't go to them.
I have two accounts. I logged into the Tibia home site on account 1 using Mozilla Firefox and was doing some account maintenance when a pop-up window appeared and invited me to change my password for account 2. This appeared several times. I logged out and ran Spybot and found DSO Exploit and removed it. My operating system is Windows 2000 Personal Edition. I am pretty sure it is at the correct patch level.
I don't know that the IE exploit DSO is anyhow related to my experience using Firefox but I have some evidence that there is a problem. I also have Norton Firewall, Norton Anti-Virus, Adaware, and Hijack This on this machine but haven't run scans with these latter yet.
What's going on? Where do I start? I am not looking for an exhaustive list of all possible removal tools but analyze the problem if you can, provide a solution or further troubleshooting steps.