Have you checked to see if the CPU cooler is seated properly?
I had a similar problem when doing the HAF X in sig, I disconnected every single cable from the mobo and reconnected them firmly and double checked. worked perfectly afterwards.
Did you get the 560 working at all or did it just die when you put the 560 and RAM in?
I know every PSU can break.. but.. it's a... Corsair! I don't think it would have blown if you just installed the card and pressed the power as the card would be idle, taking up pretty much no power! Did you have a card in the system beforehand?
Finally, what do you do in OcUK? i always thought you were tech support!
EDIT: Is the memok light on the side of mobo on the whole time? Have you got an OC profile saved to the mobo which it may still be booting to?