Abdullah, please see what Alpha said in response to your next three points relating to sin, orginal sin and punishment, but please add these thoughts to your thinking as well.
You asked that question as a human and not as a muslim I think. Why do I say that? Because you know yourself as a Muslim, that within Islam there is a hint that you as a Muslim can know you will go to Paradise after you die. But, it's just a hint, for you equally know, that the final outcome- your fate (kismet) belongs wholly to the all powerful Allah alone. It is His will which sends you to hell or to paradise. He could still judge your (any muslim, not thinking of Abdullah specifically here)arrogance and send you to hell. Islamic tradition tells you that the gurantee of heaven is as impossible to find as is a chaste virgin or pure speech.
Consequently, in order to have a chance at crossing that narrow bridge and not falling off, you spend all your lives trying to do the right thing and dogood deeds, but never being sure if you are accepted by or pleasing to Allah.
Therefore, your questions today, show that what you demand of the Christian God, you should also be demanding of the Muslim Allah. In both religions there is the knowledge that left to himself man cannot bring about his own salvation. Sin and a lack of ability to measure up to the holiness and goodness of God/Allah is well revealed in both the Bible and the Qur'an.
Both require something outside of the reach of man to produce man's salvation. Both require a life lived in such holiness and perfection, that we are able to enter the presence of the Most High God and survive.
Both religions speak of eternal punishment for those who do not measure up to God's/Allah's standards. Hell is waiting for all those who don't measure up and meet the requirements of a holy God for paradise/heaven.
In both religions, the requirements for salvation are give by the Almighty God. For the Christian it's believing that God loved them so much, He didn't want them to go to hell, he provided the only means of salvation.. the death and resurrection of His son, to pay the just requirement of the moral code.. "the wages of sin is death". For the Muslim it's living a life that believes in the creed (the Shahada) and the adherance to the six major doctrines of Islam, in the hope it will be enough.
In only one religion is the promise of salvation assured. Is the action of Almighty God, powerful and effective enough to produce the salvation of man. The Christian God promises that "the free gift of God is eternal life in Jesus Christ our Lord." For the Muslim, there is no assurance at all. Just the hope that on judgement day, Allah will be merciful.