Maximus VIII Hero won't power up

[Sam1981]

Just bought a Maximus VIII Hero with Core i5 6600K. The motherboard doesn't boot. Sometimes the on-board Start and Reset buttons are lit, otherwise they don't. When they do, if i plug in any USB peripheral in the USB Bios Flashback port, the Start and Reset buttons start to blink. Tried pressing the Bios flash button for 3-10 seconds, nothing happens. There is no Q-Code on the digital display no matter what. There is no on-board LED lit up no matter what. The CPU fan doesn't start. The ROG logo doesn't light up.

 

I tried everything I found on the web, nothing worked. What I have tried includes:
- CMOS battery plugged out for few mins and then put back in
- Used a screwdriver to short the CMOS battery connectors
- Switched the CMOS reset jumper and powered on
- Checked CPU socket pins, they are not bent or anything
- Took out the board out of the case
- Only CPU, Cooler, 8-pin CPU power and 20+4 power and CPU fan connected
- Took out the CPU and tried booting the board only
- Tried with 1 DIMM in proper slot
- Tried without DIMMs - no beeps
- Tried USB Bios flash (with BIOS update appropriately named)
- Tried on-board buttons for Start, Reset, Bios reset, MemOK

 

With the mobo and CPU included, my build is:
Skylake Build

 

Before, and currently, because the new board isn't working, my build is:
Old Core 2 Quad Build

 

I know the PSU isn't great, and should have been replaced for the upgrade. But it has no problems whatsoever with Q6600 and a GTX970 installed, even when I let it run thru the night or when I play games. One thing to note though, my old board requires only 4-pin CPU power. I'm thinking it might be a PSU issue (maybe the other 4-pins aren't working).

 

So my question is:
1. Is there something else I can try before returning the mobo
2. Is there any part in my build that requires attention, other than mobo problem

 

Points to consider (if it comes to buying/replacing parts)
I live outside the US
After spending this much on Hero and 6600K I'm really tight on budget

 

Specs:
Intel Core i5-6600K 3.5GHz Quad-Core Processor

Cooler Master Hyper TX3 Evo 43.1 CFM CPU Cooler
Asus MAXIMUS VIII HERO ATX LGA1151 Motherboard
Corsair Vengeance LPX 4GB (2 x 4GB) DDR4-2400 Memory

Asus GeForce GTX 960 2GB Video Card
Cooler Master Elite Power 460W ATX Power Supply