"Invalid parameter." Cause: You are trying to install .NET 3.5 on Windows N or KN editions (Europe/Korea). Fix: You need the "Media Feature Pack" from Microsoft first.
The installation process essentially tells the Operating System: "Do not look online; look inside this specific folder for the installation files." net framework offline installer 3.5
Once the ISO is mounted (or the DVD inserted), the necessary files are located in a specific subdirectory: "Invalid parameter