Shelter is already there in the form of your house. Heat may depend on power so if the y2k bug hits the power stations causing power outage, you may need alternative forms of heat. Like wood burners. If you are prepare for the y2k bug then you will have food supplies stored already. Keep buying new supplies every week.
Ideal items are rice and pulses.
Water will depend on your situation but good supplies are essential if the y2k bug should hit the water pumping power. Early programmers did not consider the millennium when software was created. The y2k millennium bug will force people to learn survival skills which have been lost. Many survival savvy people can help others get through the y2k millennium bug problem. Just click go once you have made a selection.