Place ham and 7 qts. of cold water in a roaster pan. Put in a cold oven and then turn the oven onto 500' and cook for 20 minutes. Turn oven off. Let sit in oven without opening the door for 1-3 hours depending on the size of the ham.
REMEMBER-DO NOT OPEN THE OVEN DOOR!!!
Then cook 20 more minutes at 500', turn oven off and let set in oven overnight.
In the morning, remove from oven and just reheat when ready to serve.