Comp not booting up

[DjchunKfunK]

I've just put my new build together. Everything was wired in, went to turn it on and the fans start and then stop immediately then it tries to do it again and still nothing. Any ideas what this could be?

 

[DjchunKfunK]

Ok I forgot to put the cpu power connector in. Now it boots, no beeps and doesn't output a display and just sits there. Fans are all on, but nothing happens. LEDs on the board have two green one amber and one red.
Full spec is as follows

i5 750
4gig G.skill ram
650w corsair psu
gt460
gigabyte ga-p55m
1tb samsung hd

 

[DjchunKfunK]

Can you believe it, I had the memory in the wrong slots Booting now, but no beeps, I thought the bios was supposed to beep once if it was posting.