making an Live DVD of one installed linux is possible, with commands, makeisofs, etc,,, but difficult.
a simple procedure: With an booted Gparted (as Gparted Live CD or Parted Magic), COPY You Linux Root partition and your Home Partition to another free, unlocated "parts" of you HDD, or to another HDD, pendrives etc,,,
When something wrong occured with your installation, you may "RE-COPY" These partitions, "into, overwriting" the original localizations, the original partitions.
If necessary, correct the Grub lines in order to access.
ALBERTO FEDERMAN NETOalbfnetoalbfneto@fcfrp.usp.brFavorite Distros: Sabayon, Gentoo, Mandriva and OpenSUSE