Set a flag (like a global bool) to "false" in the initial code/construct. Then, in the load event, set it to true. Then, attach an if/then to your resize event:

if(global.shouldShowPasswordForm){
//show password form
}

Set global.shouldShowPassordForm (a static member of a static class) to true when the program is minimized to the taskbar, and false while it is not. This will allow the program to load without showing the screen, and to be resized/minimized without the screen, as well - only showing it when the program is resized up from the taskbar. Hope this helps!