So, long story short 2 months ago I bought a brand new PC (built it yourself type of deal) installed everything, even played AH for a night on it, but the next day it wouldn't turn on, then shortly after there was smoke

Obviously it wasn't the wiring as I played aces high the night before for a few hours with No problems.
So the ASUS guy said the power supply shorted, ok I bought a new power supply - Corsair 500w yadda yadda yadda, installed it today and I get the green light on the MOBO, all fans on PSU, CPU, and GPU spinning, but the actual power light on the PC won't turn on, and there's no signal to the screen ???
Anyone here tech savvy that knows what happened, or how I can fix it plz?

P.S.: Motherboard: ASUS M5A78L-MLX Plus (read it off the box lol)
PSU: Corsair 500w
CPU: AMD Phenom II x4 965 BE 3.4Ghz
GPU: Some old like 9400GT or something
RAM: 8GB of some sort of RAM, corsair maybe