Over time, it is quite common for laptop monitor hinges to become loose, due to the frequent opening and closing of the screen. The most obvious symptom of a loose hinge is the monitor having trouble staying in an upright position. It only takes a few minutes and basic household tools to tighten these hinges. Most laptop hinge screws are found in a similar location, so these instructions will work for most laptops.
Close the laptop monitor, and turn the system around so that the back of the laptop is facing you. Look at the back of the hinges to see if the screws are visible. If you can't see them, the plastic tabs covering the screws will need to be removed before they are visible. Feel with the tip of your finger and you can feel the outline of these tabs.
Slide the tip of a sharp knife around the edge of the plastic tab, and gently pry away from the hinge until the tab pops off and the screw is visible. Repeat this step on the back of the other hinge.
Tighten the screws with a Phillips head screwdriver. Place the tabs back over the screw holes, and use gentle pressure to reapply them.