[Fyron]

SE4 has no capacity to run in windowed mode.

To use resource conversion, you have to build a facility on a planet. Then, select the planet and use the "convert resources" button (hotkey ctrl-V). You only need 1 resource converter, as you can convert an unlimited number of resources per turn. *

Resource converters are the monolith's best friend. With a monolith-based economy, you tend to have a huge surplus of organics and radioactives. Converting them to minerals every turn essentially gives you even more resources to play with. A monolith III makes 900 of each resource; if you have a resource converter III, you can convert the 1800 organics and rads into 1260 minerals, for a total of 2160 minerals per facility.

* Note that there is technically a limit to how many resources the algorithm will process in one turn in a simultaneous movement (eg: PBW) game, but it requires truly massive amounts of production to see.