Locking a cell based on drop down menu selection (Protected Worksheet)

[DRogersICF]

In cell D30, the user is prompted to select "Existing" or "Typical" from a drop down menu.

This is a protected worksheet.

If the user selects "Existing", I am trying to write a formula that 1) sets the value of cell D42 to $0.00 (the cell is already formatted to show the cell value as currency), and 2) locks the cell so the user cannot overwrite that value.

Is this possible?

Thanks in advance

[cbatrody]

Hi,

Can you please post a sample template of your workbook here?