Recently, while attempting to resurrect a Windows laptop that was no longer booting due to viruses and trojans, I stumbled upon an excellent project, and that project is the ClamAV LiveCD. The ClamAV LiveCD project is based on Clam AntiVirus, which is a GPL'd antivirus software that is available for Linux, BSD, and Windows. Since packages are freely available for Linux, Brandon Perry decided to create a LiveCD with ClamAV packages, so that computers that are unable to boot successfully can be scanned for viruses in a LiveCD environment. The project is based on Ubuntu, and has been posted to Launchpad and his personal website, which is volatileminds.net. For those that are not familiar with ClamAV, an excellent tutorial has been made available in English, German, and Polish.
This project is now up to version 2.0, and is based on Ubuntu 9.04. The LiveCD also features a Department of Defense (DoD) compliant hard drive erasing utility called Darik's Boot and Nuke (DBAN), a tool used to remove pesky Windows passwords called chntpw, a hard disk and partition verification and recovery tool called testdisk, as well as a variety of other Linux utilities.
Equipped with this disk, you are well on your way to sanitize those virus-ridden machines that end up on workbenches of computer system admins and volunteer techs across the globe.