I’ve been trying to install .NET 3.5 SP1 on my Windows 7 machine, but had a strange problem where the running installer would just do nothing. Tried using both the bootstrapper and the full version, both with no luck. After some fiddling, the following steps seemed to fix the problem:
1. If installed already, uninstall the .NET framework via Control Panel – Turn Windows features on or off.
3. Stop IIS – command prompt, iisreset /stop
4. Download .NET Framework 3.5 SP1
5. Run the installer
The installer might display an error during step 4, but .NET Framework 3.5 SP1 should still be installed correctly.