Ok so I've just got all the components in for my new and first built rig and I'm having a bit of a problem. For the life of me I cannot get the MB (gigabyte P35-DS3R rev 2.0) to screw properly into my case (Coolermaster 690). Once I get the outputs lined up properly and I'm able to put the bottom and middle screw but for the life of me I cannot line the top screws up so the top of the MB for the life of me. They are both off about half a cm and if I have one top one in I cannot screw anything else in so I have to stick with the bottom and middle and when I do that the top sags a bit as I have a Tuniq Tower HS. Should I just return the case and how normal is this?