The you don't really need those screws. I would check to make sure the rotors are properly seated against the hubs.

jack the front up and before you take the wheels off move the wheels around to see if you can feel which wheel is warped. they will always drag a little but if its as bad as it sounds you should be able to feel one wheel drag a lot as you turn it. there should be a constant resistance as you turn the wheel, if it goes from easy to hard to turn as you turn it, something is wrong.