Are we talking about the slot cover on the computer case itself? If you can not unscrew them then you break them from the case. My old HP computer had those PCI-E slots and you have to push them to remove it from the case. That being said you wont be able to re-use that slot cover any time later. I would say to push them back and forth until it breaks instead of pushing in one direction and then it flies with great force and hits something, or even worse you hurt yourself.