Do you / are you

Hi,

(Asking if someone's employed):
1. Do you work? / Are you working?
(I prefer "are you working", but I think either is OK)

2. This arrangement/relationship isn't working/doesn't work for me.
3. The European Union isn't working/doesn't work.
4. This gadget isn't working/doesn't work (returning an item at a store).

I think either can be used in #2-4 without making a difference.