No display signal on my monitor but pc is on

j.d.smittz  if you already replaced all of this “changing display wires (what wires) , monitor, changed the motherboard, RAM, then there are really not very many other options left. It is very difficult to troubleshoot with so many replaced parts. You need to be 100% sure that all of those replacement parts work. You need to ensure that your video card works on your motherboard. So let us know what motherboard this is. You also need to make sure that you know that you have a working monitor. Your achilles heel here is the communication from motherboard to video (either graphics card issue or monitor issue)