I want to use a PC power supply to output a 12V 75 Watt supply for a video camera.

If the PS puts out up to 225 Watts, will it fry my gear, or will the Gear only pull the wattage that it needs..?

Thanks in advance

It will only pull what it needs.
+1

@author: just make sure to follow one of the atx modding ibles here and be sure to add a resistor to the 5v line or you risk cooking the power supply.