Open the Command Prompt as an Administrator and type sfc /scannow . This will repair any damaged system files preventing the framework from enabling. Performance on 64-bit Systems
You are trying to install a 32-bit package on 64-bit Windows 7, or vice versa. Solution: Ensure you have the x64 (64-bit) dedicated installer. If using DISM, the sxs folder contains both architectures. microsoft net framework 3.5 1 windows 7 64 bit download
That is the web bootstrapper, not the full offline installer. It will download additional files during installation. For a true offline microsoft net framework 3.5 1 windows 7 64 bit download , you need the full ~230 MB package or the sxs folder from Windows 7 DVD. Open the Command Prompt as an Administrator and