Problem with Grub on someone eles hard Drive.

[Alfred]

Hi: 

Yesterday, I learnt how to re-write a Grub Script on my Computer because
one of my Hard drives failed, and booting up caused an Error. So I
Opened up my Terminal and did a sudo su - entered my Password. then I CD
ed to /boot/grub and made the changes and then saved the changes that I
made, getting rid of the lines that referred to the OS on the hard drive
that failed. 

Today a Hard drive in another Computer here stopped working, and Grub
was Expecting to see Windows on the C Drive, but now it is not there. So
the Drive that was the Slave drive is now the master Drive, and the
Slave Drive is gone. We can't load Ubuntu 7.04 on this computer anymore
because there is an error at bootup. I put that Drive on my Computer and
was able to get into it with my 7.10. How ever the Password for that
Drive is different than my Password. I need to be the Root for 7.04 to
make the changes to Grub. Problem is on my Machine I am the root for
7.10, and so don't have permission to make changes to the 7.04 Drive,
and then save them to the /boot/Grub/ folder in 7.04.

Anyone there know how to become the r00t in 7.04 when it is attached to
a 7.10 Computer? I know Passwd that is when you have lost the password
allows you to gain entry as root, so that you can get a new password. Or
I could just Wipe the drive, and put 7.10 on it in this other Computer.

Or I could try to boot from that Drive on my Computer, but I have
different Video components.

Any suggestions?

Alfred!