I had a fairly clean workbook and all was well. Until, that is I started
adding formulas to perform calculations.

Most of my calculations are usiing the SUMPRODUCT function so I'm wondering
it that could be the problem. There is no VBA code in the worksheet, strickly
formulas.

System Specs are...

P4 3.2 GHz
1GB RAM
ATI x800 256MB video
60GB HDD

Kick ass laptop that can run any game out there but stumbles over data
calculations? Is this normal?