move the boot-sector, how?

[Herman Aalderink]

I removed my old 15GB ATA drive no longer in use. (I thought).
Leftover are 2 80GB SATA drives (I use no more than 40GB for my simple
set-up).

My system does not boot. Apparently the boot-sector is on the 15GB ATA
drive. (I had to put back the 15GB drive).

I have a new (no-upgrade) 10.04 LTS. 64-bit system, 1GB mem.
I guess I run Grub2.

I like to move the Ubuntu-bootsector from the old 15GB ATA harddisk to
one of the 80GB harddisks. (so I can remove the old HD).
How do I move the bootsector?

With GRUB2 I suppose.
I installed grub ...... it has no 'version' cmd, so I am not sure I am
running GRUB2.
I also have gparted installed. I am familiar with its use. I noticed the
bootflag on the first partition of the 15GB HD.

I never touched grub for fear to lose my Ubuntu system access.

I have a backup of all essentials. The fastest way out of a problem is a
new install (not knowing enough tricks to do it in another way).
And not knowing enough about grub and grub2.

Herman in Philippines.