Delete record on data entry form if user closes with Firstname or Lastname field empty

[Exmark1]

I have a data entry form used to enter new customers recod in Access 2007. When opened after user types any character in any field access assigns a ID in a auto number field. If the user changes their mind they can press esc, to undo form, but if the user closes the form a incomplete record is saved. I would like to Prompt the user with a message box OKCancel Buttons that if Firstname or Lastname is null "The Firstname and Lastname must be entered" if vbOk SetFocus Firstname or vbCancel =undo record.

I would appreciate help with msgbox code

[June7]

Review:

https://msdn.microsoft.com/en-us/lib...ffice.11).aspx

https://msdn.microsoft.com/en-us/lib...ffice.11).aspx