Well as you said that could be anything from the fuse is blown down to the motor is dead... There could be a loose wire, loads of loose wires, burnt circuits, many things I'm afraid but that's the thrill of buying a machine that the seller says it won't turn on. You never know.
I've had loads where the seller has said it won't come on, and it's been a fuse or in one case there was nothing wrong with it at all and I paid 99p and sold it for £180.
Take a chance