Question PC Died

[danteuk]

My PC died.
Yesterday it was working fine and has been for years!
Last hardware change was about 2 months ago when I added a new SSD ( not the primary, not used to boot ).

Today I press the power button and the case led's come on and all fans are spinning ( case, PSU, CPU, GPU ).

But no beep, and no post message.
KB num lock light works but mouse doesn't seem to light up.

What I've tried.
I've checked the monitor and HDMI cable by plugging them into a laptop, they worked.
I've tried removing the GFX card, no difference ( plugged HDMI into onboard connector )
I've tried removing the memory, one stick at a time until no memory, no difference.
I've tried unplugging the new SSD, no difference.
I've tried unplugging all the drives, no difference.

MB: Gigabyte 78LMT-USB3
CPU: AND FX850 4.2GHz 8 cores.
PSU: Corsair CX 600 ( as supplied with PC when bought in August 2016 )
GPU: GTX 1060 6gb
Ram: 3x8gb DDR3 1600mhz ( 1 came with PC, 2 where bought and installed back in Jan 2021 )
OS: it doesn't get that far! ( but it's Windows 10 )
Monitor: I have two, I tried with both ( Samsung and AOC )
SSD: 120GB came PC
SSD: 1TB installed Dec 2021 Crucial MX500 - I already tried disconnecting it but makes no difference.
HD: a couple old SATA drives ( I've had for years ) I already tried disconnected them but makes no difference.
Case: Apache ( I think, the PC is no longer listed as a build item online ).

I bought it back in 2016 and has been working fine since, the only changes are more memory and more drives added.

Any ideas on the possible cause / solution ?

 

[Lutfij]

Welcome to the forums, newcomer!

We're going to need a little more information from your end. When posting a thread of troubleshooting nature, it's customary to include your full system's specs. Please list them like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:

include the age of the PSU apart from stating it's make and model.

 

[rgd1101]

brand and model of the psu?

 

[danteuk]

I've updated the original post with more hardware details.
PSU: Corsair CX 600 ( as supplied with PC when bought in August 2016 )

 

[teutoniswolf]

Are there any lights/beeping sounds from your motherboard? Does your PSU spin up at all or does absolutely nothing happen?

 

[danteuk]

I can't see any lights on the MB, and no sounds. ( the case lights do come on and the fans on the case, CPU and GPU spin ).
There is no fan on the MB.
I had to unscrew PSU because it's mounted with the fan down so I couldn't actually see it! but now I can see the Fan I can confirm it's spins when powered.

Some more points that might or might be relevant.

1. The mouse doesn't light up, so it looks like the mouse is not getting any data signal. ( it's a USB cable light mouse )
2. If I plug in a USB light into any of the USB ports then it lights up fine, so the USB ports are powered.
3. The case power button starts the fans and case lights, but to stop it have to long-press the power button ( so a normal short press doesn't stop any thing ).