Windows XP Macros Visual Basic

[santacatharina]

Hi! I am a new user of Visual Basic and trying to learn a little about it. What I would like to do is when I am saving my spread sheet the Macro check if the Values in the spread sheet are consistent, for example, in one day of work, the hours inserted are equal to 24hs, things, like that...
I would like it to show in the screen: -You typed the wrong hours in the cell xxx!
I already tried the command beforesave, but I am doing something wrong.
Could you please send me a example?
Thank you very much!!!