A family of Microsoft relational database management systems designed for ease of use.
You should be able to use something like:
Private Sub btnStartUp_Click()
Dim DateA As Date
DateA = DateAdd("yyyy", 1, Me.txtDateStart)
If DateA >=#1/1/2012# Then
MsgBox "Date to high"
Else
Me.txtDateStart = DateA
End If
End Sub