The only time you need to de-activate and activate modules is when you're migrating from one PC to another, making hardware changes to current computer, or changing OS.
Re-installing DCS doesn't require this since the DRM is really about binding modules to your PC, not DCS to your PC.
The "grey/green button" is just for disabling modules.
Log in to your profile on DCS Homepage and activations remaining can be found there.