Live CDs is a type of preinstallled environment.
- type your documents using a word processor, edit photos, or surf the net even without a harddisk
- have great looking graphical user interface
- troubleshoot your harddisk and recover files from a malfunctioning OS
- access your network
- test your RAM
- have a read-only OS
- play ROM-based games (Nes, Neo-geo, CPS2)
- does most of the normal OS does