when this happens to me i usually 1) do a system restore to before there was a problem
2) visit my local PRIVATE and stock up on new porno
system restore wont get rid of the problem it will leave it in background and you could still have a secuirty risk on your pc
as snoopy said goto download.com and install adaware also get a free antivirus
run both on your pc they should clear the problems
i would also recomend getting spyware doctor but dont get that untill your pc is clean otherwiseyour credit card detaails could be at risk