Although parsing the bit-mask for the date and time in the AT_INFO struct is enough to make you want to travel back in time and kick the crap out of Pope Gregory XIII, I would still encourage you to try it out. It is manageable.
Task scheduler, and Windows for that matter, didn't exist in the 80's so I'll assume that was a typo and that you meant the 90's. If you need more clarification we can help you, just ask. We only tend to avoid handing out answers because it upsets some people who want to figure it out themselves but need to be pointed in the right direction.