DDed partition - now system doesn't boot
 

I have two hard drives. One has sector errors on its second partition and locks up whenever I try reading or writing data, but the first partition (the system one) is clear... so far (chkdsk confirms). Since I know from experience that when drives start throwing errors it means they're on their way out, I used DD to copy sda1 (first partition) onto sdb1 (partition 1 of the other drive).
I then zapped the second drive's MBR (using DD again), and used Acronis Disk Director (under Windows) to recreate it from the data on the disk.

It worked, and now the second hard disk is seen perfectly if I connect it with a USB cable (i.e. I can read and write data), the files and folders are perfectly mirrored and chkdsk reports no errors; however, connected in place of the original boot drive, the computer doesn't boot. I checked that the partition has the boot flag, and it has.

What do I do to convince it to boot from drive 2?

Thanks.

Have you updated your Grub/Lilo config in order to reflect those changes you have made? Specially the root path to your kernel image to load.

What sort of interface connects the disk drive to the computer?

If you have the older parallel ATA (also known as IDE) there may be configuration jumpers on the disk drive which assign it to be "master" or "slave" devices.

The BIOS in some computers permits selection of any drive as the boot drive.

Does the drive have an activity indicator LED? If so, and if it is visible, does the indicator light up when you are trying to boot from it?

There (apparently) are ways of making NTFS bootable from a different drive than what it was originally on. Too much screwing around for me - even the linux-ntfs folks warn against it.
Linux is accommodating, Windoze ain't. Simple as that.

Well, colour me stupid. I didn't restore the MBR - I just restored the partition table. Booted off the Windows CD, selected rescue, ran fixmbr, and now it works.
*sigh*

Thanks anyway.

Thanks for reminder about fixmbr
 

Thanks for the reminder about using fixmbr. That can be the solution when lilo won't install and the system won't boot from hard drive.