Thank you for taking the time to answer.
Back when I assembled my last computer
(which is a few years ago), everything was
screwed to the frame.
It was obvious to me, that I had to screw
the rails to the drive and then slide it in,
but I tried to slide from the back, because
I did not know, that the front panel comes off
and thats the only way I was able to slide it
in... from the front.
Thanks again
Manuel