I am trying desperately to get sumproduct to work. I need to get sum of
hours before a certain date and hours after a certain date.

Here's what I'm trying to do:
IF Sheet2 A2:A50 = Sheet1 A2 (customer name match)
IF Sheet2 C2:C50 <= Sheet1 C4 (this is date, i.e. 03-2006)
Then sum up Sheet2 G2:G50 (this is hours worked)

Sometimes the formula works, sometimes it displays a 0.

Thanks in advance.