People normally think of death as the end of everything. But according to Buddhism, our life does not begin only at the moment of birth; and death too, does not imply the end of everything. If life was as simple as this, then this would encourage us to fritter away our time with no purpose. Actually, we existed before we were born, and we will have another life after death. We will be reborn in another place and the cycle of life and death will continue endlessly. The constant rebirth into this suffering world is a bigger problem than the simple death at the end of each life! Constant rebirth is difficult to solve and it becomes a critical issue when we recognize and wish to overcome it.
If you are confused by the Buddhist concept of the cycle of birth and death, samsara and all thatthe BBC has put together a video that may help explain it to you. Click on this link to see it.