I am having mini blackouts in my PC room?

I have a new Gateway PC with a 3 ghz quad core processor, 6 gb of RAM, one 8400 GS 512 mb video card, onboard sound, a 1Tb SATA drive. First it starts with the chandelier over my table blinking a little, then more and more, then the monitor and eventually the PC go off, along with the 5.1 speakers. then the whole circuit goes dead for a lil while, its a cycle, and i dont know whats going on..any help?