Since I re-install Windows OP,I have to rewrite the Grub to the MBR.

i type the command:
%Grub
%root (hd0,6) ##my linux(ubuntu 6.10) sits in hdc6.
%setup (hd0)


And I could see the successful acknowledgy.But I still boot to ubuntu.

The error infomation is:
Error 15:File not found.

What i'm amazing is that the content in the menu.lst is:
***********************************************
root (hd0,7)
kernel /boot/vmlinuz-2.6.17-10-generic root=/dev/hdc8 ro quiet splash.
initrd /boot/initrding-2.6.17-10-generic
************************************************
I tried for a few times the results are the same.
But it't sure that i see the successful acknowledgment.





when i edit it to:
root (hd0,5)
kernel /boot/vmlinuz-2.6.17-10-generic root=/dev/hdc6 ro quiet splash.
initrd /boot/initrding-2.6.17-10-generic

it says can't mount partition.

when i edit it to:
root (hd0,6)
kernel /boot/vmlinuz-2.6.17-10-generic root=/dev/hdc7 ro quiet splash.
initrd /boot/initrding-2.6.17-10-generic

after boot,it says :
/bin/sh:can't access tty: job control turned off

Have you tried just 'grub-install /dev/hdx' (substituting "x" for the letter of your booting hard drive)?

Get Super Grub Disk and run it.

I have tried the Grub-intall,it doesn't work too.

Hi cber,

A couple of thoughts for you...

If your root folder is located on partition 6 of hdc then root(hd0,x) should be 5. This parameter specifies the number of partitions BEFORE the one you want to use. The kernel line should specify the actual device which would be /dev/hdc6.

Also, what is the content of /boot/grub/device.map? This maps the GRUB hd0/hd1/hd2... etc to physical devices. I *think* it is supposed to follow the boot order of the drives as set in your BIOS.

Below are two example entries for you, whenever you modify the device.map file, re-run: #grub-install /dev/hdc

/boot/grub/menu.lst

/boot/grub/device.map

Hope it helps.

I had a case where I couldn't get grub to work in spite of doing everything right and I just ran Super Grub Disk and let it figure out what was wrong. After using it, I've just decided that I don't want to troubleshoot grub problems by hand anymore.

I made a SGD with USBDisk,It doesn't work.Another time i run LiveCD and i use df command to examine the USBDisk.
It seems something wrong(my USBdisk is 128M,but it is only 10M)
and many functions of the fdisk command don't work well.

I don't think the hd number is wrong after I have tried something.And the grub-install had said it is ok.
Now I find another amazing phenomenon:When i tried to re-install ubuntu.There is no partition at all.But I can mount some of the partitions and i can see them under windows.