Help with booting

[Beastlizard]

I'm building a comp for a friend used some old parts and some new ones he bought. I got the computer built up a tried to boot but no luck on posting then today I was going through some trouble shooting things and now it won't even turn on it will give one green led on the mobo the fabs will spin for a second then stop.

[Altecice]

Do you have all the power cables in the motherboard correctly? (24pin,8pin/4pin)? Also could you list the parts you are using