Prevent Excel User from Leaving a Cell Blank When Adjacent Cell is Greater Than Zero

Good afternoon,
I'm trying to prevent excel users from leaving the cells column Q empty when the cells in column P's value are greater than zero. Column P is an automatic calculation and locked from the user. Can you shed some light on how to do this (not using VBA). Thanks for your help.
Regards,
Saabra

Thank you mehmetcik. I'll give it a try.

Hi mehmetcik,
I tried A and B and neither worked. Thank you for your suggestion. Any other ideas?
Saabra

Thanks again mehmetcik. The attachment you provided doesn't quite fit what I'm looking for. Can I send you the spreadsheet?
Saabra

Hi again,
If you can see the attached, I'm trying to get all the columns that immediately follow the shaded columns to provide the alarm. The shaded columns are D, P, AB, AN, and AZ. The columns that need the alarm are E, Q, AC, AO, and BA. Can you see the attached?
Thanks,
Saabra

Mehmetcik,
The solution you provided would help users see when they've entered in data accidentally, but it doesn't achieve the desired goal. If I may describe what needs to happen.

At the beginning of a clinic day, users know exactly how many appointments were scheduled for clinician A. Let's say it's five. The next column asks them to enter how many appointments were kept/held. Let's say three out of 5 appointments were kept. The shaded column then automatically calculates how many appointments were missed. In this example it's 2. Then the spreadsheet is asking them reveal how many of the two were missed because the clinician failed to show. So the number in the shaded column always has to be greater than zero to require users to respond. Typically, they leave this blank and they shouldn't. Doesn't this description help?
Saabra

Mehmetcik, I tried changing the formula to what you suggested, but no result. Thanks for your effort. I'll have to let go of this one.
Regards,
Saabra