This has been my favorite spyware tool. It's widely recognized among Internet users and you will get a constant update.
The detailed information of the tool is available at http://www.lavasoft.de/products/ad-aware_se_personal.php while you can download it for free at http://www.download.com/Ad-Aware-SE-Personal-Edition/3000-8022_4-10045910.html?part=dl-ad-aware&subj=dl&tag=top5.
