Hi, Jenn1981!
This topic is the same as last question of this, just 2 minutes of difference:
http://chandoo.org/forums/topic/sumproduct-incorporating-date
I'll assume you were not sure if posted the first time...
If you'd have read the 1st forum at the main page...
http://chandoo.org/forum/forums/new-users-please-start-here.14/
...you should have noticed this points (and if you did it seems as if you should do it again):
"Consider that the world is operating 24hrs a day. A late post today may well be answered by someone else overnight."
"If you and a reader have been involved in an ongoing conversation and the conversation suddenly stops, recognize that the person may have gone to bed, even though you have just arrived at work. In the worst case a reader may go on holidays and not get back to the question for a few days."
"Never title your posts as "Urgent", "Priority" "Immediate". It may be Important to you, but not for rest of the members here. These words will be moderated out."
"Say "Thanks", whenever you can. Recognize when someone has bothered to go to the trouble and time to assist you with your question for free. Often readers will spend several hours working on a solution to a problem, a line of recognition will go a long way."
Regards!