title: qtcreator - exe does work fine inside qtcreator but doesn't outside
body: <p>I want to give a friend of mine a release build of a little project.
  It works perfectly fine when started from inside qtcreator, but doesn't open when double-clicked on the .exe file. It doesn't even give me an error message.</p>
  
  <p>Now when I tried to copy a few Qt .dll files (like Qt5Core.dll, Qt5Gui.dll, Qt5Widgets.dll) next to my exe file, it didn't change anything.
  How can I know what dependencies my project has?
  The .pro file doesn't tell me so much</p>
  
  <pre><code>QT       += core gui
  
  greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
  
  TARGET = project1
  TEMPLATE = app
  
  
  SOURCES += main.cpp\
      mainwindow.cpp
  
  HEADERS  += mainwindow.h
  
  FORMS    += mainwindow.ui
  </code></pre>
  
  <p>I'm working on Windows 7 (64 bit), Qt Creator 2.6.1 based on Qt 5.0.0 (32 bit)</p>
  
  <p>thanks for any help
  Sadik</p>
  
  <p>edit: solution can be seen in my answer</p>