Can't boot up to BIOS - diagnostic help needed.

[BenVerdon]

So, after buying a new motherboard and new processor and having known working hard drives, my rig still won't boot to BIOS. The PSU is probably the problem - but I just need confirmation.
I'm getting no system beeps - just a black monitor screen
I have used a known-working processor with the new motherboard and initial PSU and still can't BIOS. I doubt that the MoBo is the problem but I can't confirm the working processor on my old MoBo because the PSU won't power it - I think that the old MoBo is broken, as with the PSU (as there was a reboot loop (solved) but now the rig stays alive).
A new 64bit W7 has just been installed on my hard drive - fully functioning.
It isn't the GPU as the MoBo graphics also give the black screen (of disappointment, as I've come to know it).
Won't boot with RAM or without.
All fans work fine - HDD LED on the case is working - CPU heat sink works - GPU heat sink spins up, too.
I believe that the HDDs are plugged into the correct SATA ports on the board.

This thread may seem like the most simple solution ever - I'm just not game for wasting another £70 on a PSU that won't start my rig.

Specs:
i5 2500k (clocked at 3.3 GHz)
Asus P8 Z77-V LX
Corsair Vengeance RAM (2x4 Gb)
Radeon GPU 7000 series.
320 Gb Seagate HDD (for OS and music, only)
1 Tb SeagateHDD

And the glue that holds all this terror together - Corsair CX600 W (builder series)

Thanks.

 

[alexoiu]

If an internal case speaker is connected to the motherboard, start the board outside the case with only CPU and CPU fan installed. See if getting 1 long 2 short beeps.

 

[BenVerdon]

If an internal case speaker is connected to the motherboard, start the board outside the case with only CPU and CPU fan installed. See if getting 1 long 2 short beeps.

Case speaker connected - no beeps.
CPU fan fails to start up until after 5 seconds of the PSU fan spinning up (heard that's normal)
Currently stuck in a boot cycle and every other boot, the RAMok button is flashing as if there is a problem (no RAM installed, so there can't be a problem)
After 10+ reboots, the power stays is constant and can keep the CPU running until I turn it off - this leads me to believe it's a power supply issue, e.g, not enough initial power getting to the board.
After installing the other processor that I have, I found that there is no boot problem, but still no speaker beeps or video on the monitor.

I do highly doubt that it's my MoBo because it's a brand new board, however, I do understand how it could be. But don't forget that the same PSU couldn't boot a different board.
Thanks for the reply, if you need to know any more, just ask!

 

[alexoiu]

It looks indeed like a power supply issue.
Options: borrow a power supply and test, or RMA the power supply if still under warranty.
Or try buying a power supply from a vendor with a 30 day returning policy.
If not working, you can return it and get the money back.

 

[BenVerdon]

It looks indeed like a power supply issue.
Options: borrow a power supply and test, or RMA the power supply if still under warranty.
Or try buying a power supply from a vendor with a 30 day returning policy.
If not working, you can return it and get the money back.

PSU is definitely still under warranty.
Thank you!