Boot.ini is a hidden and read-only text file on the root of the system partition of that is used to create the boot loader menu. What is boot.ini? A hidden, read-only text file on the root of the system partition of Microsoft Windows NT, Windows 2000, Windows XP and Windows Server 2003 that is used to create the boot loader menu.
If you’re getting a BOOT.INI-related error, then you need to create or update your BOOT.INI file to reflect the correct system information. BOOT.INI is stored in the root of your “system” partition, which contains other files like NTLDR, NTDETECT, and a BOOT folder. The section entitled [boot loader] contains the global NTLDR settings.
If you boot a computer and an error message “Invalid boot.ini file” appears on the screen, you should know the boot.ini file is corrupted, unreadable, incorrect, or misconfigured. Boot.ini is the text file containing the booting options of a computer. For your computer to boot normally, you need to fix the boot.ini file.
If the Boot.ini file is missing, there will be no Boot.ini tab displayed in the "System Configuration Utility" panel as the image below. 2. You also can verify it by typing "C:Boot.ini" in "Start", run dialog. If you get a message of "Access Denied" or similar error messages, that explains the problem.