Question: When/how are the fates determined? "The night of power is better than a thousand months. The angels and spirit descend therein, by the permission of their Lord, with all decrees." [97:3,4] "Lo! We revealed it on a blessed night." [44:3] To Muslims, the "Night of Power" is a blessed night on which fates are settled and on which everything relating to life, death, etc., which occurs throughout the year is decreed. It is said to be the night on which Allah's decrees for the year are brought down to the earthly plane. In other words, matters of creation are decreed a year at a time. Contradicting this, Sura 57:22 says, "No affliction befalls in the earth or in your selves, but it is in a Book before we create it." This means it is written in the Preserved Tablet, being totally fixed in Allah's knowledge before anyone was created. All of the above is contradicted by "And every man's fate We have fastened to his own neck." This says that man alone is responsible for what he does and what happens to him. [17:13]
Answer: The Qur'an was sent down to the lowest heaven on the "Night of Decree" (not "the night of power" ). From there it was revealed to Muhammad (pbuh) over 23 years according to the situation warranted. The previous verse is speaking about the Qur'an : "[God swears by] the manifest book (the Qur'an) that makes things clear. Indeed We sent it down in a blessed night...."
After God wrote all things in the Preserved Tablet, every one already had everything since his birth to his death written. This explain the prophecies that can take thousands of years to happen. We are still having the free well. While I was writing this piece I had the will to do something else like watching the news. Our brain will never be able to reconcile this fact. We just have to beleive in that as we believe in the law of creation that everything is created except the creator himself. Religion is about faith of the unseen. We first have to be very sure that the Quran is from God. When we have the compelling evidences we have to accept the few unseens mentioned by God as real facts.