The vast majority of computer users don't know or care about the underlying technologies that drive the gadgets and utilities they access on a daily basis. Most of these users run Windows and have little idea of what to do when things go wrong. Perhaps the drive won't boot or files are corrupted, random messages pop up, the registry or the file system is broken. The problem may be blamed on a root kit, a broken program, or a virus. Sometimes the data is lost, and sometimes the user gets lucky with a rescue disk supplied by one or other of the anti-virus vendors.