you know what? SP3 installs the Malicious Software Removal tool, too. try updating, and see if that finds/fixes anything. control panel -> automatic updates, and set it to the top (installs automatically). set the time when it updates to around an hour from now, and it'll get the files when it's time. it'll take a while, fyi, but it's totally worth it.
if not, then go to a tech support forum.