Ad-Aware Free has long been one of the most popular spyware killers on the planet, and with good reason. It's simple to use, does an excellent job of detecting and killing spyware, and stays out of your way as much as possible. The fact that it's free for personal home use doesn't hurt, either.
The newest version of Ad-Aware Free improves on an already solid product, notably by expanding its protection. At first glance, the program looks substantially the same as previous versions. Tell it to scan your system, and it finds spyware and other malware, and then deletes it or quarantines it for you. But even though it looks and works largely the same, under the hood there are a substantial number of changes, primarily aimed at beefing up system protection. Ad-Aware Free now protects against rootkits, which are stealth attacks designed to escape detection and burrow their way into the operating system. Ad-Aware also includes several types of heuristic detection, which protects you by examining complex system behavior, rather than just looking for known malware signatures. If the program's heuristics work as well as do the heuristics in other anti-malware software, it should provide better protection against emerging and unknown threats, as well as threats that are already known.
In addition, Ad-Aware Free promises to protect you against malware that tries to restore itself after a system reboot. And it now integrates with Internet Explorer to scan files as you download, alerting you to any malicious files you may send to your system.
Also new to this version of Ad-Aware is a "Simple mode" that lets you set your configuration once, and never have to do it again. If you prefer, you can toggle to Advanced Mode, where you can select advanced features for customization.
Note that Ad-Aware Free doesn't protect against viruses or provide full real-time protection. To get those features, you'll need an antivirus product. Lavasoft's for-pay products, the $27 Ad-Aware Plus and the $40 Ad-Aware Pro, include antivirus protection--though it's not yet clear whether those products are superior to their antivirus competition.
The upshot of all this? The newest version of this popular piece of software is well worth the download. If you don't already have Ad-Aware Free, this is a good time to try it. If it already lives on your PC, go ahead and upgrade to the new version.