This protective wall is created by a process called virtualisation, whereby one piece of software running on your actual PC creates a software environment that acts like it is your actual PC - it creates a virtual PC or buffer zone. The trick being, the software running inside this virtual PC is completely isolated from your actual PC so if it tries to do something untoward it doesn't actually harm your real PC. All that's required to get rid of the harmful software is to delete the Virtual PC and start again.
Now, virtualisation software has been around for a while and there are plenty of solutions that enable you to run software in this way. However, none have ever been quite as easy to use as this one. Setting up BufferZone is as simple as running an installer and rebooting your PC. That's it, you're protected.
By default, the BufferZone protects Internet Explorer, Windows Media Player, and MSN Messenger so anything that is downloaded through these programs is kept in this pseudo quarantine. What's more, any script or hack that exploits security holes in these programs is also blocked by the invisible wall of the virtual PC.
You can also assign any other program to be run in the BufferZone, like your preferred web browser, peer-to-peer applications, IRC client, and email clients (in the case of email clients, the client itself isn't run in the BufferZone but any attachments or other saved files are). There's also an option to run all software from other locations - like CD-ROMS and USB drives - in the BufferZone. So, baring a direct attack on your operating system, your computer has the potential to be totally safe.
The best part, though, is that as well as allowing programs to be run in the buffer zone, entire programs can also be installed there. So, if you want test a piece of software that you think might be dodgy, you can download it and install it (registry keys and all) within the BufferZone and see if anything bad happens. If all is well you simply uninstall it from the BufferZone, move the installer to the safe zone and install it again.
The icons and windows of programs, files, and folders in the BufferZone are encircled by a red line, so you always know if you're working in a secure or unsecure environment. However, if you find this distracting you can disable it in the configuration menu.