No power? on new build

I am building my first system and I have run into an issue. So far, all I have connected to the motherboard is: cpu w/heatsink and fan, case fan, front panel lights and front panel power switch, and ram.

When I turn it on, nothing happens. Fans don't move, lights don't light, etc. I tried to reseat the 4 pin cpu power and the 24 pin power cables. It was then I noticed something odd about the 24 pin power cable.

In the picture, look at the 5th pin on the top, counting from the right. It doesn't have the gold lining like the other pins do. Is this ok or is this a product defect?

Thanks for any help.

I forgot, loose ram will not boot nor incorrect ones.

the most common mistake is using the 12 rail plug try moving it to the left side or center it or put it on the right side

the left side usually works

that thingw ithout the gold pin is to indicated how to put it in there should be an empty one on ur 24 pinner

Thanks to all who responsed.
What I have done now:
I removed all connections from the motherboard.
I removed the heat sink/fan from the cpu, removed thermal paste, then reapplied it again (incase I had put too much on previously). I plugged the power back in to the motherboard. Plugged in all fans. Plugged my front switchs. Put memory back in.

Now I turn on the power (in the back), then hit the power button on the front and ...

The power light on the front lit very briefly, then went out. None of the fans turned on. When I tried to turn the power on again, the light did not turn on.

So, it looks like I got power, however briefly.
But something caused it to shut off quickly.
Can anyone suggest something I could check? Or something I can do?

I had a similar issue when i built my first system. I found out quite quickly from help from a friend that i had forgotten to put in the standoff's. In hindsight now that i understand more it is such an obvious error, but it was really that simple. The motherboard sitting directly on your case backing will kill it. Good luck.