Windows XP SP2 lacks a required update for digital signatures.
: The standard offline installer usually contains English. If you need a different language, you must download the specific Language Pack separately after the main installation is finished Microsoft Learn that is requiring this framework? Installing the .NET Framework 4 on Windows XP
This is the most common source of confusion. You must download Windows Installer 3.1 (or later) for the .NET setup to execute.
In the small office of a vintage-PC enthusiast named Marco, a battered Dell running Windows XP SP2 hummed like a treasured relic. He’d rescued the machine from a recycling bin because it held a suite of legacy software his small business still used. One afternoon a client sent a file that required a newer runtime Marco didn’t have: .NET Framework 3.1. He knew modern systems had moved on, and that dealing with older Windows versions often meant hunting for offline installers and working around missing updates.