I'm currently trying to get a used Celsius W530 (MI5W) with Xeon E3-1281v3 CPU and 32GB RAM up and running again, the main board is a Fujitsu G3227-A12 GS2. The machine was used at some office before and came without any hard drive. It has ports for DVI, DisplayPort and VGA and an Nvidia NVS 315 video card with DMS-59 port.
The machine immediately turns on without pressing power button as soon as the power plug is plugged into the socket. However, the monitor remains black, no power-on or BIOS message, the monitor seems to fall back to stand-by mode after a few seconds, although the workstation appears to be loading from the DVD (I tried to boot it from an Ubuntu-Linux installer) and the inserted empty hard drive is also being tried. The monitor does not seem to get any signal at all, although it does detect that it's a digital or analog connection. I have tried all video ports without success: VGA, DVI, DisplayPort-to-DVI, as well as graphics card DMS-59 with adapter to DVI. The same happens with another monitor via VGA.
What is the problem and what can I do to get this great machine up and running again?