System initial setup, black screen during memory configuration

I have a set of 3 dell poweredge xr4510c servers, we have turned them on twice before, both times simply connected a monitor to the DP, a mouse and keyboard, powered them on, and then were brought to some setup screens. Stepped through them until we hit an OS screen, and then powered the server off as we were not ready to install and start work yet. We only did this with one of the 3 servers.

That was last week.

Now when we go to turn any of them on, we see the dell poweredge screen, then it switches to a loading screen and shows "Initializing intel ultra path interconnect", Then it gets to "configuring memory" and after just a moment the screen turns black.

Same behavior on all 3 blades.

I did look through the manual before starting, and again after encountering problems, but didn't see anything related to this.

Any help would be really appreciated.