computer don't start

hi my computer won't start, I can hear the fans going and the light on the motherboard is on but the lights on the front panel aren't on and the computer isn't booting up.
I have a computer with a a8n5x asus motherboard and the northbridge fan was not working so I opened it up removing the video and sound card. I laid the cards on cover which is metal. I don't think I let static electricity damage any since I was touching the metal parts of the cover and the computer stand.