program in excel vb function?

This isn't exactly what you are asking for but its a way to have a date highlighted.

Say you want to highlight all dates in column B within say 30 days of today...

-Select the cell you want to monitor

-Select Format\Conditional Formatting

--Condition1:

---Cell value is between =Today() and Today()+30

---Format: background color

OK

Each day you open the workbook, the cells with this conditional formatting and have dates before today and dates within 30 days will be highlighted.

You can do this with a macro and either run it on WorkBook_Open or call it with a keyboard shortcut.

Open your workbook.

Copy this macro to the clipboard:

Sub CheckDates()

Dim rng As Range

Set rng = Range("B1:" & Range("B" & _

ActiveSheet.Rows.Count). End(xlUp).Address)

On Error Resume Next

For Each cell In rng

cell.Select

If ActiveCell.Value <> "" Then

If DateValue(ActiveCell) = DateValue(Now()) Then

MsgBox (ActiveCell.Address(0, 0) & " contains today's date")

End If

End If

Next

End Sub

Next, press ALT + F11

Insert > Module

Paste the macro into the module space to the right.

Close back to Excel.

Go to Tools > Macro > Macros.

Highlight this macro, if it is not already highlighted.

Click 'Options'.

Select a letter to be used as a keyboard shortcut.

Close back to Excel.

Press CTRL + your shortcut letter to run the macro and identify all cells in column B with today's date.

To have it automatically run when the workbook is opened:

Press ALT + F11

Double click on 'This Workbook' in the Microsoft Excel Objects. (upper left).

Change the 'General' dropdown menu to 'Workbook'.

Type "CheckDates" (no quotes) between Private Sub Workbook_Open and End Sub.

Close back to Excel and save the workbook.

Now, every time the workbook is opened you will see your 'reminders'.