i use the disk to enter the 'rescue mode'.
and then i run 'chroot /mnt/sysimage'
it's ok, and when i run 'grub-install /dev/hda',
there is something wrong and the hint is
the file /boot/grub/stage1 not read correctly.

finally,i choose another method

i run 'grub' after i run ' chroot /mn/sysimage'
grub>root (hd0,5)
grub>setup (hd0)

Oh, there is also something wrong, the hint is
"Running "install /boot/grub/stage1 (hd0) (hd0) 1+16 p (hd0,5) /boot/grub/stage2
/boot/grub/grub.conf" failed"


can u tell me how can i do?

hd0 windows2000
hd6 red hat 9.0

Maybe you have a separate /boot partition?
If you do you need to point the root (hdX,X) in grub to that, not your actual root filesystem.