If you're using a userform for the input, don't let the user leave until it
satisfies all of your critieria:

'Validate form data
If Me![YourFirstRequiredTextbox] = "" Then
MsgBox "No value entered.", , "Missing Data"
Me![YourFirstRequiredTextbox].SetFocus
' Exit the subroutine; clear memory of any objects
GoTo SubExit
End If

If all of them are similar, you can loop through the controls collection.

Hope that helps.
Sprinks


"Help?" wrote:

I have developed an excel file that customers will fill out questions, which
transfers that data to another excel file, converts to csv and distributes to
a printing facility. A problem that I am having, but do not know how to
correct is that customers are forgetting to answer some important questions.
How can I make excel not allow them to go forward without answering a
specific question?