How the heck do I turn it on?

[V8Ian]

House sitting and my sister needs her computer turned on. The monitor is on and displaying the message "check signal cable", the box is titled HDMI.

190404

My instructions, second hand, were on the box behind the monitor. The box has WS embossed into it and apart from the cable to the screen, there only seems to be a LED, presumably to indicate on/off. I cannot locate a switch, any advice greatly appreciated.

190405

[V8Ian]

Stop panicking everyone, in the dark, confined space, I found another box with a switch. The computer is now on.

[Saitch]

Were you in the dark? Get out!