Seriously, and this is only a personal perspective, but I think you really need to invest in a "How Databases works" book as well as a VB
and Access book.
Ok, where you disable and enable the subform is totally up to you and how you want it work. If you want to trigger the enable from 3 combos, then go for it.
Why would you need to refresh... Im not entirely sure you would need to refresh, I merely said you would probably want to. The subform data is related to your comboboxes? I assume it is, but then I spose it doesnt have to be! If it is related to your comboboxes and the subform is disabled while you have been playing with the comboboxes, no doubt when you enable the subform it would be a good idea to refresh the data, wouldnt it? Test it out, see whether you need it.