Ok the powering off may just be the way the bios is set, you may need to hold the power button in for 5 seconds to power off.

Have you had no display ever? That does suggest lack of power as a cause, but after reading a review on you case that shouldn't be a problem. Have you plugged in the main ATX power, large rectanglar plug, and the 12v booster(???) , the small square plug, on the motherboard ?

Try reseting the bios, there a good clear instructions and pictures in the NF7 manual.

If it powers up and then turns of after a minute or so, this sounds like a over heating CPU problem. Try giving the cpu a good clean, with a alcohol based cleaner so it evaporates and leaves no residue. What CPU cooler did you get and what type of heat paste?

Also try only having the power switch plugged into the mobo, I don't think the others will cause a problem but the more options you elimiate the better.

Let us know how you get on and best of luck mate.