I would say it's most likely that the power supply can't supply enough power to the system. If that is correct then you will need to buy a new PSU. Purchase a good make like Seasonic, CWT, Corsair, Thermaltake, Enermax, Gigabyte, Coolermaster, Antec, etc and try and get one with a single 12V rail if possible. I would advise you to get one of about 650W minimum depending on your hardware demands.