You will need to open the skpye.exe shortcut in your STARTUP folder. Go to properties and put the /nosplash /minimized in startup options.
Enter in the "Destination" Field :
C:\Program Files\Skype\Phone\Skype.exe" /nosplash /minimized
It works fine for me, after 2 mintues - no more annoying Skype windows. But the software starts automatically at windows startup - minimized.
Thank you all !!