try this: "DELETE * FROM OrderT WHERE OrderID=" & OrderID

Actually, if you just want to make sure you are only making new orders that have details, you could probably remove the refresh and the statement, then just do

me.undo

Then it would revert back to blank new record and not save anything

Try before update event with that if it doesn't work in close

Thanks Abraham and Adam. Unfortunately neither of these worked. Im still thinking it has something to do with timing or maybe not even achievable in the onclose. The me.undo worked in the beforeupdate event but the problem there was it didn't then let me add the order details, just run the undo lol. I managed to get a delete command button (Wizard Macro)  to delete the record even on dirty so i tried to replicate that in the on close event but failed. I tried both Macro and converting the macro to VB but im a novice at this still so probably got it wrong.

Try using the Form_Unload event instead (with your original VBA code).

First, check out if you get prompt by the Msg box
if you are not getting the msg it's the count that doesn't work.

Thanks Kevin & Abraham, The code worked in the form unload event.  But then presented another issue. If the user exits the form before entering any data then the form as it closes loads up and displays the first record before closing the window. (I have the orderID created as soon as the form loads) So i removed the code so when the form loads OrderID starts off as NEW but then the Dcount errors because there is no ID "Run-time error 3075". Im now wondering if a better approach would be to capture the orders with no details as a separate operation and not actually delete a record but instead mark it as deleted with a check box.
I heard that storing Boolean values in the Tables is not a good idea - would it be then better to not use check boxes for this and use a status table with PK 'Cancelled' and a PK 'Active' and use this in the order Table and orderdetail table.

You could add this to only run the code if there is an OrderID:

If Not IsNull(OrderID) Then
        ' add other code here
End If

BOOM! Thanks Kevin