Installing .NET Framework 4.7.2 on Windows 7 is not a "double-click and done" process. It requires manual intervention, specifically the SHA-2 updates (KB4474419 & KB4490628).
On that online computer, download the following three files: net framework 4.7 2 windows 7 sin conexión
Take the USB drive to your offline Windows 7 machine. You must install these . Do not skip or reorder them. Installing