Spybot Search & Destroy (Windows, Freeware)
Spybot Search & Destroy has made quite a name for itself over the years, earning accolades from both general and computer-focused publications. Spybot Search & Destroy is the highest ranked freeware tool at 2Spyware.com, a website that ranks malware removal tools. In addition to scanning for malware, Spybot Search & Destroy also has a variety of additional functionality, including a botnet scanner, hosts-file modification (to keep malware from calling home), a secure file shredder, and a dummy code feature (it replaces malicious or questionable adware modules with inert code so the dependent program will keep functioning). As an added bonus Spybot Search & Destroy is compatible with every version of Windows dating back to Windows 95.
SUPERAntiSpyware (Windows, $30)
SUPERAntiSpyware is available as both a freeware and premium edition like Malwarebytes' Anti-Malware (see below), but the level of restrictions on the freeware edition are considerably higher. The free version is limited to basic on-demand scanning and malware removal. The premium version includes real-time scanning, registry protection, a scheduling service, auto-scan on startup, and 50 startup diagnostics to stop malware infections before they spread. One of SUPERAntiSpyware's strongest selling points is its high level of compatibility with other protection tools like Avira, Kaspersky, Symantec, and McAfee. In most cases it can be run along side other tools without any conflict.
ComboFix (Windows, Freeware)
ComboFix is just as spartan as the screenshot here makes it look. You download ComboFix, run it, and it takes care of the rest. The basic ComboFix process looks like this: It backs up your registry, checks to see if you have Windows Recovery Console installed, and then it goes to town on your system scanning away through 40+ stages. When it's done, ComboFix spits out a log file and lists all the malware it found, which ones it was able to remove, and which ones you'll have to use your Google-fu to look up how to remove manually. It isn't fancy, but it gets the job done and gives you a detailed report at the end to take to security forums for help if you need it.
Malwarebytes' Anti-Malware (Windows, $25)
Malwarebytes' flagship application Anti-Malware is a shareware malware-removal tool. The principle difference between the free and premium version of the application is real-time monitoring. If you don't need active scanning against threats, the free version uses the same database and does an admirable job ferreting out infections. Anti-Malware was, for example, one of the few malware removal tools that could detect and remove the Antivirus XP 2008, a spyware application that masqueraded as an antivirus app. The Anti-Malware installation includes another application from Malwarebytes called FileASSASSIN—a helpful tool for deleting files locked by Windows.
HijackThis (Windows, Freeware)
HijackThis stands alone in this Hive Five as being the least automated yet most likely to completely wreck your system if used incorrectly. HijackThis does a comprehensive scan of the state of your computer and reports back an enormous log file. The tool makes no judgement on whether or not an application, browser modification, or registry entry is malicious or not. It simply generates a list of things that could have been potentially altered or tampered with by spyware, malware, or other malicious programs. Advanced users can look over the log themselves and determine what needs to be pruned. If you're not comfortable doing that, your best bet is to take the log file to a popular security forum like BleepingComputer or SpywareInfoForum and ask their armies of knowledgeable volunteer malware slayers to comb over it for you. Alternately, while not a replacement for receiving expert help from people in the forums, HijackThis.de is a web-based HijackThis log reader which is updated nightly. You upload your log file, it scans the file for relevant entries and gives you links to articles on how to remove the malware found in the log.
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