My intention is to buy the program but then I have to get an explanation of Why does the sound sometimes kind of dissapear when I am ready with my work? Mostly it happens when I have put on sequenses with several sounds and then corrected them to right positions.
I also wonder if it is possible to keep my songs from trial to the program I will buy?
Without seeing a screenshot of the arrangement it is difficult to tell what is happening. If you could post a screenshot of the area where the sequences 'disappear' it would help and give some more details of exactly what you do and at which point a sequence 'disappears'
Yes you can keep your arrangements - make a back up copy as well before installing the full version if you get it on disc.
Assuming you have download the trial version you will only have to buy the licence and enter the codes supplied.