stability test and ARDL test

[louizabadis]

Hello all;
Ihave three questions.
The first one was posted two often in this forum but still no response.
Second, I need a precision about the equation used to test the stability of my model. Do I estimate equation with original series (which is spurious REGRESSION) or with stationnery séries.
Thired, can I use the ARDLbound test even when i have one (or more) série that is upper than I(1).
Please answer.