I am using Excel 2007 and have a spread sheet of 800 columns and 163,000 rows. In each cell of the first row are equations similar to this: =VLOOKUP(F4,Sheet2!$A$1:$ADT$571,H$3)-VLOOKUP(G4,Sheet2!$A$1:$ADT$571,H$3)

I am trying to copy down this row to row 163,000 and am only able to get to around row 15,000 before I get the message that I have run out of system resources. I have tried turning off auto calculations in the cells. What else can I do to populate the cells with the formulas?

Thanks.