Old Faithful settled back into its quiet hum. The fan slowed. The hard drive clicked one last time, then fell silent.

Locate the downloaded file (usually named ndp48-web.exe ) and double-click it.

.NET Framework 4.8 requires Windows 7 Service Pack 1 (SP1) . If you haven't updated to SP1, the installer will fail. How to Download and Install

Navigating Microsoft .NET Framework 4.8 for Windows 7 (32-bit)