First Build. Initial Boot Fail... Help Needed

[pdgillam]

Attempted my first build tonight using Lifehacker and TonyMac guides with tonymac's "CustoMac Pro Build".

Hardware

CPU-Intel Core i5-3570K
Motherboard- GA-Z77X-UD5H
RAM- 16GB 1600Mhz DDR3 (2x8 GB)
Case- Corsair Carbide 500R
PSU- Corsair 650 Watt Modular
Storage- SATA 6Gb/s 240GB SSD
SATA 6Gb/s 3 TB HDD
​

Motherboard power button is lit. When I hit the power button the only response in the turning of the fan in the PCU for a couple seconds. Like I said this is my first attempt and I am not sure where to go from here. Thanks.

 

[Stork]

Since we're not telepathic, please list the steps you took to get to your present stage including how you downloaded Mountain Lion.

Additionally, what graphics method/card are you using.

 

[pdgillam]

The guide said that the graphics card was optional. I am just using the MB integrated graphics with the hdmi port.

Step 1. Removed side panels from case. Attached an antistatic wristband. Placed case on its side and mounted the MB. The case had built in standoffs so that wasn't necessary.
Step 2. Removed the temporary cover of the CPU. Installed my CPU by matching up the arrows. The lever and cover went down smoothly without having to apply any force. Mounted fan on top with the 4 pegs locked in place.
Step 3. Installed RAM in DDR3_1 and DDR3_2.
Step 4. Installed the HDD in the second bay with the toolless mounting. Installed the SSD in the top bay and mounted it with the hard drive screws provided by the case.
Step 5. Installed power supply (fan up).
Step 6. Connected everything to the PSU- in the order I connected it- MB, HD, HD to SATA port, back panel fan, CPU, CPU fan, USB 3.0, HDMI, Firewire (F1394), then all the front panel headers. I initially had the + and - backwards, but I switched up correctly I believe.
Step 7. Plugged in power cable, plugged in monitor via HDMI, flipped the power switch, hit the front panel power button only to have the PSU fan briefly spin as my only result.
***Update****
Turns out I am an idiot and didn't have the RAM properly inserted (I know that should be like the easiest step).
The PSU fully turns on along with the CPU fan. However it is going in like 5 second intervals of on then off, on then off, etc. LED by the power button on the motherboard says 15 and an LED light by the B BIOS is on. No signal on my monitor though.

 

[pdgillam]

Had already purchased Mountain Lion for my macbook. Just redownloaded it from the App Store. I only have minor experience btw. This is my first actual full build of any sort.