Hello, my computer was working just fine, them I decided to use a vertical mount from cablemods to showcase my graphics card a bit. I got it installed and turned it on and no signal to my monitor. So I put the graphics card back how it originally was and still no signal. I put it into another slot and nothing. I tried my other graphics card in both slots with no luck. I tried my standard HDMI and display port on both and nothing. I plugged them into my motherboard and got nothing. Normally when my PC starts and works, the keyboard does its flashing but that isn't happening at all. I don't know what the problem could be. It's seated properly. The graphics cards both light up and the fans come on. Could anyone help or tell me if something went wrong and I need to replace something. My thought is the motherboard.
CPU: Ryzen 7 2700x
Motherboard: MSI x470 gaming pro carbon
Ram: 16g Corsair vengance rgb
Main graphics card: MSI rtx 2080 gaming x trio
Secondary graphics card: Nvidia GeForce 1060 6g FE
Psu: EVGA 750w 80+gold
It was working just fine before I tried that vertical mount
It's probably you disconnected the signal wires from the motherboard to the case on/off switch. Since you don't have power to anything. Many power supply's have a on/off rocker switch - perhaps you turned off that switch.