debian cd boot parameters

[Frederico Rodrigues Abraham <devotion97@gmail.com>]

    Hi. I am willing to install a second operating system on one of my
partitions and am afraid that it will scramble my disk boot sector.
    In case this happens, how can i recover it later?
    I could boot into my linux through the cd and run grub-install to
reinstall my boot sector...
    Unfortunately I haven't been able to boot using the cd...
    I use the line: linux root=/dev/hda8 (my / partition) but i get a
kernel panic for having no valid root on hda8... is this because I
have an ext3 partition and the cd kernel does not support it?
    How can I do it?
    Thanks
    -- Fred