The Amnesic Incognito Live System (TAILS)

 

Tails, or The Amnesic Incognito Live System, is a security-focused Debian-based Linux distribution aimed at preserving privacy and anonymity. All its incoming and outgoing connections are forced to go through Tor, and any non-anonymous connections are blocked. The system is designed to be booted as a live DVD or live USB, and will leave no digital footprint on the machine unless explicitly told to do so.

Tails isn’t the kind of operating system that you want to install on your hard drive. The Tails developers specifically configured it to forget everything that you’ve done when you reboot. While that doesn’t make it a good general purpose OS, it does mean that running off of a USB, you can load Tails whenever you want to use a computer privately and anonymously.