"Winfixer" has now been identified as a security risk.
I would strongly recommend you employ a pop-up blocker. If you're using IE, you can download the Google Toolbar which employs an excellent blocker, or you can configure it to block pop-ups by changing your security settings in the "Tools/Internet Options" menu. Click on the "Security" tab and the "Custom Settings" button. You can then scroll down and click "enable" on the pop-up blocker option. Mozilla's Firefox also employs an excellent blocker.
Robert will (of course) deny there are any pop-ups/pop-unders on his website, but if you've configured your Browser to "clear cookies" when you close it (or use Norton's "Clean Sweep"), you are at risk of encountering "Winfixer" when you visit his site.
This has been a public service announcement and is not intended as a flame.