This setting in the BOOT.INI file controls which operating system the NT Boot Loader launches by default if none is selected.
Change the attributes for BOOT.INI so it is not 'Read Only', BOOT.INI is found in the root directory of the first partition. Then open the file using Notepad or another text editor (not Microsoft Word or any word processor).
Under the [boot loader] section change the 'default=' option to one of the operating systems listed under the [operating systems] section that you wish to use as the default.
For example, to load Windows NT from the first partition on the first IDE hard drive in the /WINNT directory the option would look like:
default=multi(0)disk(0)rdisk(0)partition(1)\WINNT