USB key unlocks any computer

Pocket Desktop pocket operating system
$19.95 for four-gigabyte version; $39.95 for 8 gigabytes; or $59.95 for 16 gigabytes at getthekey.com

You can’t carry a complete desktop computer in your pocket, but here’s the next best thing--a USB device that lets you turn any laptop or desktop PC into your own machine, while preserving your privacy.

The Pocket Desktop contains a copy of the Linux operating system, and a stack of popular free software. It’s also got a good deal of empty storage space where you can stash music, photos or documents. You just plug it into a computer’s USB port and reboot the machine, while holding down the “boot menu” key--usually the F12 key. This makes the computer boot from the USB drive instead of its own hard drive. The process takes a few seconds.

Now the computer becomes your own. You can use the Pocket Desktop’s software to create or edit documents, send and receive e-mails, or play favorite tunes. Once you’re done, just reboot the computer and unplug the Pocket Desktop. Your secrets are safe, because everything stays on the USB drive; nothing is stored on the PC.

The Pocket Desktop is more expensive than it ought to be, given its use of free software and the low cost of USB flash memory. But it’s an excellent way to protect your privacy when using someone else’s computer.