A Live CD is a CD that has a bootable operating system, such as, Ubuntu that can run completely off a CD and independent of the hard drive. A Live CD distribution could also be used to troubleshoot, fix, or maintain
a Windows or Linux computer. Live CDs have become very important troubleshooting aids that can also be used to scan and remove viruses from hard drives. Because the operating system is on a read only CD medium, viruses cannot permanently infect the operating system. If a problem does occur you just simple reboot the computer to a fresh operating system. You could also use the Live CD to transfer important files from a nonfunctioning computer to other media or even a network drive. Live USB flash drives have the advantage of transferring files or configuration changes directly to its media making it an even more powerful tool.
I use Live CDs, bootable CDs and bootable USB flash drives daily for maintaining a lab of over 30 computers. I can quickly configure, repair, or image an entire hard drive in minutes. I can also use these tools to completely replace an operating system or change to a different operating system again in minutes. These tools have become a very import aid in maintaining large numbers of computers. The savings in work time using these tools is huge. What took me hours or days I can now accomplish in minutes. I image over 30 computers each morning in less than 10 minutes, which provides a fresh operating system for my students. I can even switch to a different operating system or configuration for a completely different class in minutes. Before using these tools I was a slave to my lab computers, but now the computers are the least of my problems.