If you are unable to boot another copy of Windows to access an NTFS partition, you can use the free TeraByte Unlimited EditBINI DOS utility to edit BOOT.INI on an NTFS partition.
If the reason you need to update BOOT.INI is an invalid "partition(w)" entry and you don't have any way to fix it (either via another OS copy or by adjusting the order of partitions in the MBR) and the OS boots entirely from the C: drive letter, then you can use the following work around:
- Make sure the partition table is loaded with your target partition.
- Begin the Win2K/XP Setup.
- At the menu choose 'R' for Repair.
- At the repair options menu choose 'C' for the Recovery Console.
- Type cd \ and press ENTER.
- Type rename boot.ini boot.x and press ENTER.
- Reboot the system and boot the item with which you were having trouble. You'll get an error that BOOT.INI is missing but it will still boot the OS.
- Once the OS is up and running, you can rename "boot.x" back to "BOOT.INI" and make the necessary adjustments to BOOT.INI (you'll have to remove the read-only/system attributes in order to update it (i.e. attrib -s -h c:\boot.ini).