Security screws appear on products which manufacturers don't want consumers to open, and require specialty screwdrivers to remove. You can track down and purchase the specific screwdriver used, but an easier method is to cut a standard slot or Phillips head into the screw using a rotary tool.
Instructables user thematthatter demonstrates how to use a rotary tool with a fiberglass-reinforced cutoff wheel to cut a slot drive head into a security screw. (Rotary tools are often referred to as dremels as the Dremel brand is the most popular type, but you can find good rotary tools from many manufacturers at any big hardware store.
With practice you should be able to cut a Phillips drive head as well. Remember to take all safety precautions and wear safety glasses when operating a rotary tool. Keep in mind that modifying or removing security screws will almost certainly void your manufacturer's warranty.
How to open security screws [Instructables]