One possibility is a graphical warning, applied with conditional formatting.

Example: if you want to be alerted whenever B1 remains blank you could apply
to C1 the following conditional formatting:

Format--Conditional Formatting

Condition 1: Formula is: =ISBLANK(B1) and have the color displayed a bright,
garish color.

If you want an actual dialogue box to pop up, with a text message telling
you that B1 is blank, then you would have to write some code.

Dave


--
Brevity is the soul of wit.


"Dileep Chandran" wrote:

Hello everybody,

How can I get a warning message, if I enter any text in A1 and left B1
blank and proceeded to C1?

Appreciate any help in advance

Thanks

DC