Yeah, I just pulled the power supply from workstation 
Cameron;  it was a bit of work with so much packed into that tower case.  I'll run tests on the power supply (a tester costs $30 US);  I 
hope it's the power supply;  that's not too bad to replace.
I also put my Poser runtime, content zip storage, software downloads, Poser scene files, and Silo modeling files on a secondary drive, rather than on the C: drive.
Oh, if you ever try to power a PC up and it seems utterly dead, yet the power supply tests good, then it is likely that the motherboard has developed a fault, and the power supply shut itself down as a safeguard.  Replacing the motherboard would mean I'd need to convince the publishers of all of my installed software -including Windows- that this is the same machine.
One pre-emptive strategy for hard drive failures is an 
Acronis backup license ($80 US for three PCs/Macs).  It will copy your entire C: drive -including windows- as a compressed disc image file to an external hard drive.  A single 8TB HD can hold backups for all four of my workstations, which have 1TB or 2TB C: drives, plus one or more 1TB/2TB secondary drives.
Subsequent backups only need to copy whatever has changed since the last backup.
On the other hand, I got three new (new to me;  they're 8yr old enterprise refurbs) server blades put into service: 
Andromeda, 
Epona, and 
Europa.  

  I've been running 120V AC power lines through the house so that every group of four blades will have their own 20A electrical circuit.  I'm doing a similar project upstairs in the workstation room, so that each workstation is on a different circuit.
Once I get all this AC power wiring completed, I'll get back on rendering big skydome panoramas in Vue, for use as skydome textures for Poser, D/S, Carrara, et al.
With 
Andromeda, 
Epona, and 
Europa added, the 
PixieHollow network will bring 480 render threads to bear on those big tough Vue atmosphere renders, with a total core*clockspeed factor of 1,430!