this is my first build, I bought a merc alpha bit fenix case that holds 3.5" hdd. I bought a 3.5" barracuda hdd model st1000dm003 but it will not fit, the instructions say to just slide it in but i just cant. i measured the drive and it is actually 4" so idk how that's possible when its model is only 3.5". idk if i need to bend something but again, very vague instructions. please help because im scratching the hell out of it. Answers are greatly appreciated!