No, don't do anything like using a screwdriver, the risk of damage is too great if you don't hit the right bit.
As to turning on you use the power button on the case, the board should be connected up just as it would in the case, it sounds like you have removed all the wires as well ?
This is why using the motherboard box is a great help at such a time, use that to sit the board on (straight on the cardboard), it allows you to hang an edge over the box lip, to allow the video card to sit in normally, and with the case right next to it you should have enough cable in the case to reach it, no need to worry about USB connection plugs (the multiple collection of wires should be all that's needed), we just need the system to fire up, or not, it will help figure out if we can take a leap of faith and say the board is faulty.