Complex sentence: Microsoft shipped abroad a "master version" of Windows, either on a disk or via encrypted electronic transmission, to foreign manufacturers who first used the master version of Windows to generate copies, and then installed the copies onto the computers they sold to users abroad.
Split into simpler sentences: Microsoft shipped abroad a "master version" of Windows to foreign manufacturers, either on a disk or via encrypted electronic transmission. Then the foreign manufacturers used the master version of Windows to generate copies, and installed the copies onto the computers they sold to users abroad.