Computer power supplies are one of the most crucial components of gaming computers. Low power and low quality power can cause an array of problems , that may give you indications of problems in other components of your computer, just because those components are not getting the voltage necessary to operate as they were designed.

The new high end graphics cards are requiring extreme amounts of power to operate.  Stock power supplies require computer builders to decide which components can actually operate correctly under heavy gaming loads. Start with the basics with a capable power supply (500w) minimum, and never worry about powering all of your components.