|AKDOS, Hard drives pull less than 1 amp. If the PSU is that close to overload it needs to be bigger as others have stated. |
Two other possible causes for the short run time could be improper installation of the heatsink/fan including the thermal paste/pad. You must have a motherboard stand off installed under every mounting screw and ONLY under the mounting screws.
Even if one of my points is valid, you still need a good PSU of adequate capacity. A single +12V rail is best. Also, top mounted PSU cases are best.