Restrict cell entry based on another cell

[Jeff Gentry]

I would like to restrict data entry in cell D4 based on entry in C3. To be more specfic, if there is NOT an entry made in cell c3 than I do not want the person to be allowed to enter anything in cell D4. I only want to allow entry in D4 if cell C3 is NOT blank. I thank you in advance for your assistance.

 

[njimack]

With D4 selected, go to Data>Validation. From the Settings tab, change the 'Allow' drop-down to 'Custom'. In the formula box, enter =$C$3<>""