"Adguard is a third-party web service that allows you to download Microsoft Windows and Microsoft Office ISO images from Microsoft services directly....One of the better options to get those is provided by the Windows ISO Downloader program for Windows. You may use the program to grab ISO images of Windows or Office versions or editions straight from Microsoft servers....The Adguard website offers an alternative. If's biggest advantage over Windows ISO Downloader is that it is a web service. You need a modern web browser to access it, but don't need to install programs or plugins to make use of it...downloads are quite fast considering that they are served directly from Microsoft servers and not third-party servers." -gHacks
This might be of help for those of you looking for older version isos (but also current ones)...