If you are running win XP with service pack 2 you need to activate the pop up blocker in Tools- Internet Options- Privacy and tick the box to block popups, alternative solution is to use another application like Firefox to browse the net ... get it free here http://www.mozilla.org/products/firefox/
Another nice solution is the GoogleBar (http://www.google.com/googlebar/) - free, easy to use, and it also offers easy access to Google search and form completion - you give it your name, address etc once, it fills in forms for you where these are required.
I'll stick my tuppence worth of support for using Mozilla's Firefox browser - It's fantastic.
It's also incredibly easy to use and I don't think I've had a single pop-up since I started using it.
At only 4.5Mb - definitely woth the download from here;
http://www.mozilla.org/