Grub to Grub2 query

[squareyes]

Hi,
I have Ubuntu 10.04 installed with Grub (legacy?) and an external
hard drive with Ubuntu 11.04 installed with grub2.
Both with Grub in the mbr.
I wish to remove the external drive with 11.04 as machine will not boot 
with this drive disconnected,
but there is no 11.04 entry for me to edit in menu.1st file.

Will installing Grub2 on my original 10.04 give me a file that I can 
remove the 11.04 entry from Grub?
or will it present me with problems? I have checked out the archives, 
but obviously am not asking the right questions
on searching, as I can't find anything relevant there.
Many thanks in advance.
Take care
Winton