I recently noticed that whenever I visited certain non adult related websites I got a barrage of adult popup windows. I then found out this was a virus, the virus is called JS.Fortnight.B@mm which is activated by the following means,
"The mass-mailer arrives in infected e-mails, that have the signature as a "s.htm" file, so when the infected e-mail is open, using IFRAME, the virus remotely executes its infector (another html) and infects the current user."

The above text was taken from this page,

Its damn hard to remove and I found the following thread at a techie forum,


Anybody else come across this menace and if they did how did they get rid of it.