two days ago I built my first computer. I was so happy to see it turn on, but then when i plugged in my monitor, alll I got was a no signal sign. `the next day I tried again, and it worked! now I'm back to the same situation. All the fans are spinning, but none of my peripherals work. I tried front and back I/O, and now I'm at a loss I want to use my new pc again, does anyone have any idea what happened?