Brand new computer, wont start

[baddweather]

Alright, its not a BSOD, so I apologize if this is in the wrong section, but my new (and first) computer build will not even start up. When I press the power button, all of the fans spin for a fraction of a second, the HD beeps once, and nothing else. It seems to randomly do this 2, sometimes 3 more times in succession and then nothing. Someone told me it was probably CPU fan, which was unlikely because of how new it all is, but I did replace the heatsink paste and still got nothing. A suggestion for what I could try, or even a nudge in the right direction would be very appreciated.

CPU: Intel Core i5 3350p
MOBO: Asus P8B75-M/CSM Micro ATX LGA1155 Motherboard
HD: Seagate Barracuda Green 1TB
Memory: PNY XLR8 8GB (1 x 8GB) DDR3-1600 Memory
GPU: Zotac GeForce GTX 560 Ti 1GB Video Card
Power: Topower 500W 80+ Bronze Certified ATX Power Supply

 

[Tmagic650]

Did you connect the 12 volt AUX connector to the socket near the CPU?

 

[baddweather]

Yes it is, as far as I know everything is connected correctly, and I've had several people recheck it for me

 

[Tmagic650]

Pull the PC completely apart and make sure the motherboard has all the standoffs in the proper places not to short it to the case. You might even try to run the computer outside the case

 

[baddweather]

I tried that today, I took it all apart and tried to run it outside the case, same result. I ended up moving it out in the garage to work on it, and now it will boot up, and stay on.. something its never done before. I hooked up a monitor with an hdmi cord and cant get a display. also the red LED is constantly lit on the front, the one next to the cylinder.

 

[Tmagic650]

So it powers on now and stays on? "also the red LED is constantly lit on the front, the one next to the cylinder" What is "the cylinder"? Probably a bad motherboard...

 

[baddweather]

I forgot to mention I think it stays on now because the garage is much, much cooler. and its the symbol on the front right below the power LED, its a cylinder with a circle above it. Im prepared to buy a replacement part, I'd just like to be sure what I need to replace now,

 

[Tmagic650]

That cylinder symbol is a hard drive activity LED