When my RH 7.1 machine boots, it should have only one image option to boot
from at the start-up screen, i.e., "Linux".  That is how it has been since I
intalled it several months ago.

But now there are two image options: "Linux" and "Linux bak".  What is Linux
bak?  I could not find anything in English at google.  Has my system been
comprimised or something?