I have a Win32 app that creates a simple window, I need to call that program/window from another program (cryengine). My app starts at
int WINAPI WinMain(...)
You don't have to go the DLL or static library way to just launch your program from another program.
However, finding & activating (SetForegroundWindow) will only flash the window button in the taskbar so that it gets user's attention. This is done by Windows so that other apps cannot interrupt and cause usability issues.