Possibly bad psu?

So i believe my PSU may have kicked the bucket. I have this Antec power supply: http://www.newegg.com/Product/Product.aspx?Item=N82E16817371012 I got a few years ago.

For about a month now I've been hearing a loud high pitch whine coming from the computer which I believe is from the PSU. It sounds like those annoying "mosquito" tones. This morning I tried to turn it on but it wouldn't stay on. It turns on for about a half second(fans spin and everything) then puts out an audible click like when you force a power off(hold power button) which I'm guessing might be a safety switch or something. Followed by everything turning off.

I'm not completely sure if it's the PSU but if it is what would you guys recommend I replace it with? I was looking at something about 600w (1000 was just overkill as I don't plan on dual carding any time soon). Not sure what effect the certification has but the higher the better I guess.


Edit: Figured I'd add in my current PC part list for reference: http://pcpartpicker.com/p/2jqPy

GPU: Sapphire 6970

CPU: 4770k(no OC yet)

RAM: 16Gb Corsair Vengance 1866 C9

Corsair H100i

1x WD 1TB Sata 3GB/s 7200 rpm

1x WD 2TB Sata 6GB/s 7200 rpm

Other power drawing components include a few fans and maybe an SSD in the future.

The Corsair CX series is pretty good and affordable, also comes in a modular form. There's a 600 watt version so it would suit you nicely.