Spybot - Search & Destroy Portable is a free security program that scans for and removes malicious or unwanted adware, malware, spyware, and other threats on any compatible Windows PC without requiring you to install it. That's because it's been portable-ized by PortableApps. Its download contains everything you need to run Spybot without the program making any changes to your PC, beyond purging junk, that is.
Spybot's portable application installer (.paf) can save the program's executable to virtually any directory, including a USB thumbdrive. Spybot's interface consists of a two-paned main window and a navigation sidebar accessing the program's main features: the main Search & Destroy tool, a Recovery tool, an Immunize feature that protects Web browser, and Update and Donations buttons. Before we initiated a scan, we clicked the Help button, which not only offered a good manual but also a tutorial that walks new users through the program's various steps, complete with illustrations. Under Search & Destroy, we clicked Check for Problems. The scan is thorough and took several minutes; it turned up some minor issues that we could check out by expanding the scan display's tree view. We selected those items we wanted to remove and clicked Fix selected problems, which Spybot did after double-checking our wishes. The Immunize tool adds sites known to be bad to your browser registry's Restricted Zone, if you're running IE or Opera. It blocks such sites from running executable code on your system.
Spybot also offers an Advanced mode that can potentially remove things you want to keep, so use it with caution. It offers a ton of interface language options, too, on the Languages menu. Spybot - Search & Destroy Portable is a great tool for your portable PC toolkit, the one you keep on a USB drive for when friends and relations need help with a PC problem.
Spybot - Search & Destroy can detect and remove a multitude of adware files and modules from your computer. Spybot also can clean program and Web-usage tracks from your system, which is especially useful if you share your computer. Modules chosen for removal can be sent directly to the included file shredder, ensuring complete elimination from your system. For advanced users, it allows you to fix Registry inconsistencies related to adware and to malicious program installations. The handy online-update feature ensures that Spybot always has the most current and complete listings of adware, dialers, and other uninvited system residents.
According to Spybot, the paid version gives you "six times as much detected" (their words, not mine). That means it MISSES five out of six dangers. The reality, of course, maybe even worse!
The 'free' version is window dressing to get you to buy the expensive version. It's effectively a toy. Which is a tragedy, as for many years, it was ONLY free, and it was the best anti-malware option out there. Not any more.