Does a case need to have any wires?

Ok, i guess that was a bad way to ask the question….but, here…
So me and my friend are building my new computer tomorrow, (mainly he is)and the motherboard i ordered is too big for my case i have. So i got a case from a friend, but it doesnt have any wires what so ever. Now i was just playing around with my old computer and stuff. and i realized, it wasn’t turning back on because i had unplugged the Power SW, Power LED, and H.D.D. LED. So i was wondering…does the case have to have those wires or anything else to make it work? Because the case i have is just a case…nothing else.