Computer not working, even after replacing major parts

[xserpx]

Hi there,

My 2 month old computer recently stopped working for some reason - I turned it on and the resolution was messed up, and I couldn't access BIOS. After resetting the CMOS, it wouldn't boot up at all. I did a breadboard test, it still didn't work. I've tried a new PSU, a new motherboard and now a new CPU, and am still getting the same problem. I have no idea what's wrong, but the LEDs come on and the fans come on, but the 'boot_device_led' on the mobo stays lit, no matter what I do.

My set up is:
Intel Core i7 4790K Processor
Corsair H100i Liquid CPU Cooler
ASUS Sabertooth Z97 Mark S Motherboard
Corsair Vengeance 4 x 4GB Memory
Samsung 840 EVO 250GB SSD
Seagate Baraccude 2TB HDD
EVGA GeForce GTZ 780 Ti GPU
Corsair 860W ATX PSU
TP-Link PCI-e Wi-Fi Adapter
Windows 8.1

I'm starting to think the problem must be something really simple, but I honestly have no idea what it could be.

Any help you can give me would be appreciated!

 

[DasHotShot]

Try turning off/unplugging the PSU, removing the MB battery and waiting for like a few minutes.

Reinsert and attach power leads, try booting and heading right into BIOS if it works now and make sure all your memory timings etc are set to default.

It sounds like a mem problem to me to be honest