Does it matter if I screw in all of the spots on the motherboard? I'm trying to screw in the last screw on the motherboard and it won't screw in, it's really loose and wont tighten no matter how long I spin the screw driver. Also, does it matter if I use metal screws for the dvd drive, I didn't know I was supposed to use these plastic things to screw in the dvd drives so I used the same metal screws I used for the motherboard.