I currently have this formula on my main sheet today:

=IF(ISNA(VLOOKUP($B6,prin_received_091807.xls!$A$8 :$H$98,3,FALSE)),0,(VLOOKUP($B6,prin_received_0918 07.xls!$A$8:$H$98,3,FALSE)))

My issue is that on my prin_received sheet I do not always have the same
columns. So I basically want to do an if then statement.

If week1 (column heading on sheet a) matches week 1 (column heading on sheet
b) then do the vlookup else output zero.

I am not sure where to go from here so any help is appreciated.

Jonette