Im new here so sorry if I do anything wrong. Recently I bought all the parts of a computer individually and put it together and plugged in a monitor. When I turned on the computer nothing happened on the monitor and when I tried to shut down the computer by holding down the power button nothing would happen. The only way to shut down the computer was turning off the power supply or unplugging the power supply. Can anyone tell me what is wrong? Nothing happens on the monitor, theres is no operating system installed because nothing happens to the monitor so I can't do anything, I sent back the motherboard and cpu and got a new one but they could be defective again so I am completely lost and have no idea what is wrong