PC doesn't power on - help needed with diagnosis process

[Aa83]

Bit of background around my issue:

I turned on my PC this morning, which for some reason seemed to go into the BIOS for about a second, after which point the PC powered itself off. I didn't hear any popping or other unusual noises, there wasn't any smoke, I haven't changed anything recently in term of hardware or settings, and I didn't see a leak from my AIO cooler. I tried turning the PC back on via the PC case power but to no avail. At this point I had to catch my bus to work, so switched the PSU power to off, unplugged the kettle lead from the PSU, and left it as is.

When I get back to the house this evening I'm planning on doing some diagnostic testing to see exactly what has happened here, so I thought I'd post on the forums in the meantime and ask for opinions and suggestions for my plan of action. Here is my setup which I'll be testing:

CPU - Intel i5 3570K
Motherboard - Gigabyte Z77X-D3H
RAM - 8Gb GSkill Ripjaws 1600
CPU cooler- OCUK 240mm+ AIO
GPU - MSI r9 290 4G
PSU - Super Flower 1000W Platinum
Case - Corsair Carbide Air 540

Here is my diagnostic testing plan:

Step 1. Wall socket
Test wall socket with another known working appliance
if appliance does not work, problem is with the wall socket
if appliance does work, move onto step 2

Step 2. Extension lead
Test extension lead with another known working appliance
if appliance does not work, problem is with the extension lead
if appliance does work, move onto step 3

Step 3. Power lead
Check power supply kettle lead on another known working appliance
if appliance does not work, problem is with the kettle lead
if appliance does work, move onto step 4

Step 4. PSU
Plug a PC fan into PSU, jumper green and black 24-pin wires with paperclip to turn PSU on, set PSU switch to on, set multimeter to 20V, test voltage on molex and 24-pin cables
If no voltage is seen from the PSU, RMA the PSU
If correct voltage levels are seen, ensure the power cables are plugged back in correctly and move onto step 5

Step 5. PC case
Clear the CMOS and jumper the power switch on the motherboard
If the PC does not power on, motherboard is likely the issue
If PC does power on, the case power switch is likely the issue


Can anyone see anything wrong or missing from my plan at all? Something I may have overlooked or could also be causing the power issue?

Cheers!

 

[TWiNKLeT0Es]

Clear the CMOS?

 

[darknite]

Is the cpu power connected? Either a 4pin or 8pin connector depending on your motherboard.

 

[Aa83]

Clear the CMOS?

Ah good point thanks, I'll add that before the step where I'm jumpering the motherboard power switch.

Is the cpu power connected? Either a 4pin or 8pin connector depending on your motherboard.

Cheers for the reply, yes that was plugged in alright (it's a 4 pin) though on that point I suppose it's also worth checking the cables are all plugged in correctly after I've tested the PSU.