Windows only: Free application Hitman Pro scans your system for malware using not one, not two, but eight different anti-malware applications. Essentially, Hitman Pro is a helper utility that runs up to eight different cleaning tools when you tell it to. Some are favorites we all know and love, like Ad-Aware and Spybot S&D, while others are a bit more obscure. The idea behind Hitman Pro is that you've got a one-stop shop for killing off any malware that hits your system—regardless of whether it's spyware, adware, or some nasty virus. As the MakeUseOf post points out, scanning your system with each app can be a time-consuming process, so it's best to use when your computer is idle. If Hitman Pro seems like overkill, check out our five best antivirus applications and five best Windows maintenance tools for some great alternatives.