Microsoft does not seem to bother with older software. It is because they don&#x27;t support and upgeade it anymore.<p>Microsoft only goes against piracy of software they still support and upgrade.<p>They don&#x27;t bother with the old software because it isn&#x27;t worth it to sue or send a c&amp;d letter because they don&#x27;t earn an income with it anymore. So they don&#x27;t lose income if someone pirates software they no longer sell.<p>In fact they gave away the source code to an early MS-DOS and MS-Word as part of their own open source license.<p>It is good PR for them if someone emulates their old software in the web browser and gives them free publicity.