Recovering from the Windows Virus

I had to replace a dying hard disk. This was as easy as connecting the old (still set up as master) and new (jumpered to be slave) drives and booting Knoppix. At the command line:
# dd if=/dev/hda of=/dev/hdb

When it’s done, shut down, remove the old drive and make the new one the master. Then everybody was happy. But not really. I’m not sure if the dying drive barfed while copying part of the Windows partition or what, but WinXP failed to start complaining that <Windows root>\system32\hal.dll was corrupt. So I reloaded Windows and it wiped GRUB off the disk. This is fixed by booting Knoppix again and entering these steps (which are specific to my configuration of /boot as the first partition of my boot drive) from HOWTO Restore GRUB:
# grub
grub> root (hda0,0)
grub> setup (hd0)
grub> quit
# reboot