If you don’t want to have to lug a laptop around, just so you can access files and use specific applications you depend on, it's worth investigating thumb-sized versions of software that are both stored and launch from a USB memory key.

Such a setup allows you to keep data and applications on a thumb drive. USB utilities are available to make your drive work as a clone of your desktop, which you can access thereafter via any PC, whether or not it's connected to the web.

Most impressive is MojoPac. It's the truest version of a mobile desktop we’ve seen to date. After you install MojoPac on your thumbdrive and add data, the MojoPac desktop, a custom interface similar to a regular Windows desktop, pops up.

Here you can install any Windows application, just as if you were using a regular PC. MojoPac even temporarily transforms your thumbdrive into your system's C: drive. Once you have installed an app on the MojoPac-enabled thumbdrive, it will work on virtually any computer you plug the thumbdrive into. It takes some time to wrap your brain around it, but the software works well and is compatible with any USB device, including Apple’s iPod.

Unfortunately, the software costs $50 (about £25) after the 30-day trial expires. You can obtain similar functionality from the $30 (£15) Ceedo, which includes a number of applications within its system. However, you’ll need a second $30 piece of software, called Argo (downloaded within the Ceedo program), to run applications—such as Microsoft Office apps and Lotus Notes— that are not part of the system.

Another $30 option is MigoSync, a program that lets you synchronise email, share data files, and replicate the look and feel of your desktop. Unlike MojoPac, however, MigoSync won’t let you store and carry any applications that aren’t already designed for installation on regular thumbdrives.

If you’re a do-it-yourselfer, you can manually outfit a thumbdrive with the data and the applications of your choice. The result isn’t the seamless experience that MojoPac offers, but it works pretty well.

Your first stop should be PortableApps.com, which is stocked with free programs that will run directly from a thumbdrive without requiring a standard Windows installation.

If you’re a fan of open source, PortableApps provides plenty of alternatives, ranging from Firefox to OpenOffice to GIMP (the Photoshop alternative) — all are ready to run from your preferred USB device.