as Rick as stated it is not always possible to find a find answer to any question within orthodoxy. This does not mean that orthodoxy does not have any answers but it does suggest that it is always appropriate to have a measure of humility when considering any question.
I often begin my own consideration of any question by turning to St Cyril of Alexandria and St Severus of Antioch. These to speak with one voice. In their writings of all is a loss of the indwelling spirit of God who is true life through Adam's sin man has lost the gift of immortality and in corruption which is experienced through the presence of the holy spirit. Finding himself alone he experiences his own mortality and the true death as separation from God.
The cause of this loss is the turning of Adams will away from God and towards his own pleasure. The will is the locus of sin in man's heart. Sin has no existence apart from in the will of man. It is not a thing. It has no hypostasis, no reality. But the consequences are very real, first of all through Adam's sin the loss for all men of the grace of incorruptibility and immortality, and the indwelling spirit. And in our own lives an increasing darkness and the liability to judgement.
But St Cyril and St Severus are clear, we are not born sinners though we are born mortal. It is possible to imagine that a man might choose always not to sin, yet in the reality of human existence only one has ever been able to choose God in all ways and at all times, Jesus Christ the incarnate Word. And even were a man to avoid sin all of his life, that is always to have his will turn towards God, he would remain mortal and corruptible and devoid of the spirit, having done no more than was his duty.
Within orthodoxy the beginning of a man's experience of salvation is not found in his particular predestination to life, but in the incarnation of the word who renews human nature and in himself restores to it the grace of immortality and in corruption. My faith, baptism, and participation in the Eucharist we are united with this renewed human nature, and Christ becomes for us a second Adam. Salvation begins not with the exercise of human will whether free or constrained, but with the free choice of God who offers salvation to all.
What then of the human will? It seems to me that the fathers teach us that the human will is never so corrupt that there is not some possibility of turning towards God, and this turning, however imperfect, is in some sense an exercise faith that draws from God the grace of the holy spirit to nurture and perfect it.
As Rick has already said, St John Cassian exemplifies the Orthodox perspective on grace, and does so much more than St Augustine. Indeed St Augustine's views on grace, predestination, sin and the fall, are almost entirely rejected by orthodoxy. Orthodoxy tends to the view that man is not so corrupt that he cannot still choose God even while that choice is itself compromised by passions, appetites and sin.
But the first turning towards God is not the fullness of life in the spirit. Indeed if the spirit is our true life then we will discover as Christians that we become more and more alive as we root ourselves in the life of the spirit. True freedom is only experienced in the spirit and so Christ is uniquely free, but calls us all to enter into the freedom of life in the spirit. If my first choice for God is weak and halting and shadowed with ulterior motives that I can barely understand myself, then this should not be so for my second choices, my 10th, my hundredth, and so on and so on. As a Christian I should be becoming more free and more freely exercising my will, and the proper exercise of free will is not found in being able to choose other than God, but in choosing only God.
What about our choices for self and pleasure rather than God. This is not the exercise of free will, this is the exercise of a constrained will, bound by habit, natural animal appetites, and the sin dominated environment. We are not free when we make these choices, we are free when we choose only God. Yet orthodoxy, unlike Calvin I believe, does not believe that man, created in the image of God and with an immortal soul that is always called heavenward, is left so devoid of grace and natural spiritual instinct, but is unable to call out to God with faith at any moment. Yet this is no work of salvation, this desire for God and for the transcendent implanted in our nature is itself a gift.
Orthodoxy would insist that all are called, and that all have the possibility of responding, however imperfectly. This imperfect response is but the beginning of life in the holy spirit. True freedom of will is found not in this first hesitant turning to God, but in a life lived in spiritual effort and self-denying spiritual exercise.
As I sit here assailed on many sides by various temptations I am aware of this at least that I am free enough to make right choices and if I choose the wrong it is not because I lack the freedom but it is because the freedom is not habitually exercised by me.
This is only a poor introduction to the Orthodox view on this subject, and it could be much improved by others. I would be very interested in your response.