A few years ago, when I was young and green, I got the same message and deleted SULFNBK.EXE. As I recall I replaced it by running sfc to get it off the disk. If that fails, you can always re-install, although that sometimes creates problems of it's own. I don't use McAfee, but Norton can be set to check all your incomming e-mail. And for god's sake, don't use Outlook! Most viruses are designed specifically for Outlook.