I don't want to sound like a pain in the behind area, but you are still not very clear.
All you ask is: "Is it possible" and "Can I".
So to answer your questions, the answer is yes.
Try to give some more relevant info like where the dates are located on the sheet and when do you want to be reminded (when you open the file, open the sheet, manually run code, etc....)
Here is a simple code which checks the date in A1 and compares it to today's date. When there is 5 or less days to go a popup appears. The is done whenever the sheets containing the date in A1 is activated.
Private Sub Worksheet_Activate()
If Range("A1").Value - Date <= 5 Then
MsgBox "5 or less till due date"
To implement the code, right-click on the sheets name and select "view code", paste code on big white field.