Ray, a couple questions, I'm not very familiar with excel, is it possible to make the "white" cells read only?
Steiner, unlock the green cells and then protect the sheet as follows:
Select a green cell(s), right click, select Format Cells.. > Protection and remove the check from the “Locked” box.
Repeat for all green cells.
Go to Tools > Protection > Protect Sheet..
Check the “Protect worksheet and contents of locked cells”.
It’s OK to leave the password entry blank.
In the bottom window uncheck everything except “Select unlocked cells”.
Now excel will only let you select the green cells.
Al