Video card makes pc have no power

i recently had a issue with my pc. it had no power. bought a new power supply, didnt help. and then got a new motherboard. put it all together and had power. went to put the video card in and nothing. then power doesnt work for a couple mins then works again. power supply is more then enough watts. its a gforce card. pretty low end since i just need it to actually run the pc. what would cause the power to stop b/c of the video card?

please list the specs of your computer, so we can determine its power needs and any potential compatibility issues.