As absic says that is a good PSU. I am using the HX850 in my main machine and it has put up with many things that I have thrown at it without grumbling. If you can afford the extra the HX is even better as it is modular and a slightly better build again, it even comes with a seven year warranty!!
Yes, I was just looking at that PSU and think I will get it instead. All them cables bundled up inside a case look's horrible. Modular is the was to go.
Although the most likely cause of the problem is the low power of your PSU, you could take the time, whilst waiting for the new one to arrive, to do as Dark Mantis has suggested and double check that you are not getting a short circuit from somewhere.
If you look through this thread: http://forum.giga-byte.co.uk/index.php/topic,5704.msg45814.html#msg45814 I explain how to test the components outside of the PC Case. This is always a useful step as you will then know if there is a problem with the basic hardware or, if everything fires up outside of the PC Case, that there is a possible short circuit when you are putting everything together inside it.
Another thing to double check is that you have connected the cables from the power and reset switches on your PC Case to the correct pins on the motherboard header.
Thank you very much, that's very helpfull. I will check everything again now.