1st, most 250 motors have self fastening shafts, so when the props spin off, it is very likely that you mixed CW and CCW, means for example you put a CW motor where you need a CCW motor. I tested it a while ago,.
To make sure that you did not mix anything here, check that: NW motor spins clockwise, NE counter clockwise, SE clockwie, SW counter clockwise (NW meanin North West, the prop front left in straight flight direction).
Your second problem, that it does not take off, may be connected to 1: motor spinning direction and propeller direction do not match: the props must be attached in a way that the air ist pushed beneath, if one or two props are wrong, the quad will flip, if three or four are wrong the quad will stick to the ground. I attached a photo of a proper setup with Nighthawk 250 and 5045 Props.
A less likely possibility would be, that you quad ist too heavy, so that the props cannot lift it. I could not manage that with a 250, even with 5030 props and 2S batteries my Nighthawk would lift off (although no fun to fly).