Ad-aware
From Lavasoft

PC World Software Product of the Year (2002), Best Freeware *

Ad-supported software (like the sponsored mode of Eudora) has been around for years, but as software companies struggled to survive last year, many took ad support to new heights. That's how adware--software that downloads advertising while you use the associated application or at random--was born. This insidious trade, in which adware skulks onto your hard drive and can invade your privacy online, has proliferated, frustrating more than a few Internet users. Some people call such programs spyware, because in some cases they permit advertisers to continuously monitor your online activities.

There wasn't much anyone could do about adware until Lavasoft created Ad-aware, a simple, free program that scans your computer for the telltale files that adware plants on your system--and deletes them. Ad-aware regularly offers users fresh reference files that enable the program to find the latest spyware to invade their system, much as virus definition files help antivirus software clean up Windows. A one-of-a-kind utility, Ad-aware does its job quickly and efficiently (much to the chagrin of spyware makers), and it has become an indispensable tool in the fight for online privacy.

The two paragraphs above are reprinted from the PC World web site: http://www.pcworld.com/reviews/article/0,aid,97429,pg,4,00.asp

Clicking on the start menu will begin a scan of your system for potential adware files.

After Ad-aware completes its scan, you can then select which files you want to delete or quarantine.

Then with the click of a button, Ad-aware will provide you with the confidence to surf the Internet knowing that your privacy will remain intact.

Download Ad-aware

Ad-aware is compatible with Microsoft Windows 98/Me/NT/2000
and XP Home and Professional.