I am assuming the previous OS was loaded on the the smaller hard drive?
I would use 'fdisk' to set the new drive active and see if it boots properly. Make sure you have the boot floppy handy, because you will need it to restore back to the oroiginal drive should it not work. The boot floppy must have 'fdisk' on it.
the 'boot.ini' controls the multiboot options. Other system files need to be at the root in order for the new hard drive to boot properly. Those are likly to control the results you get.
Okay, so here's what i did.
I planned to switch my OS over from my 40 gig Hard drive to my 80 gig one. I installed Windows XP Professional as a new install and installed it on the 80 gig drive. Everything looked like it installed correctly, and i was thinking that it worked, but now when i turn on the computer, it has the multi boot option, where i select which OS i want to use. If i take out either drive, it won't boot.
What i want to do is get rid of the multi boot option, format the smaller hard drive, and use it just for files. But, like i said, any time i remove the 40 gig drive the computer does not boot.
Any ideas on how i can fix this? the Multi boot thing is getting annoying!