Here is a critical detail for retro-computing enthusiasts: Windows NT 3.1 was originally distributed on CD-ROM and 1.44MB floppy disks (22 disks!).

The term Windows NT 3.1 ISO is a modern convenience. In 1993, CD burners cost thousands of dollars, and the ".ISO" file format was not a household term. When you download an ISO today, you are downloading a digital reconstruction of the original CD media or a converted set of floppy images.

An authentic ISO image of Windows NT 3.1 contains:

Assuming you have your ISO mounted and a blank virtual hard disk (CHS: 1024/16/63, ~500MB), follow these steps:

In the late 1980s, Microsoft partnered with IBM to develop OS/2. After the partnership fractured, Microsoft pivoted, hiring key digital equipment corporation (DEC) staff—most notably Dave Cutler, the lead architect of VMS. Under Cutler’s direction, Microsoft rebuilt an OS from the kernel up, resulting in NT. The “3.1” versioning also helped market NT as a seamless upgrade path from Windows 3.1.