I had an occasion yesterday when I found that a password to a website had been cancelled as the site said it had been used too many times,including in Japan and Germany .I got it reset altho' I hadnt been responsible as I am the only person using the PC.
I found that using Spybot S+D several instances of Smitfraud-C but Spybot wasn't able to delete them so i printed out the log..
I went in to Regedit and found a load of folders( about 45) mainly with porn related url's under the above key and deleted them all.I ran Spybot again and they were definitely gone.
I take it that there is a connection betwen the two things.the password useage and the Smitfraud-C instance.
i also use Norton Ant-Virus Internet Security/AdAware/Spybot and Spyspotter.