Once again me with more problems. The PSU of my new build (the AMD-FX one) has already had some kind of problem, so I returned it to 1A for a replacement. After almost a whole month (they certainly took their time), I got the replacement PSU (a new one, the same model - Chieftec GPS-500-A8). It seems that there is some kind of a problem with the new one too:
When the PSU was hooked up as it should be, the rig wouldn't boot/POST/do anything - the only activity was the Power LED on the case and the green power LED on the graphics card (Asus GTX660), which states that it's recieving power all OK.
When I tried to turn on the rig without connecting the PCIe 12v connector to the GPU, at first it seemed that it was going to start up as normal, but the wires of the PSU started to emit a burning smell (I bet it was the 12V wire in the 24-pin connector). I turned it off with the PSU switch. Tried this multiple times, but always the same result - first couple of seconds OK, smell of burning wires, turning off in fear to lose a piece of equipment.
However, when running it with an ancient S3 Trio (or maybe ViRGE) PCI graphics card, I could get into the BIOS as normal.