The black bar on the edges of your screen are probably caused by a setting in the DIsplay section in Control Panel. Play around with the resolution figures and you should find the right one that fills the screen.
If it's a small hatch on the base of the machine and not to remove all the screws to open the case, it probably just needs clicking open once you've loosened the screws. An old credit card or plastic hotel key is better than anything metallic.