Tower turns on, keyboard, mouse, and monitor don’t

Hi! So my computer is a cyber PowerPC and when I turn it on, the mouse, monitor, and keyboard will not turn on.. the lights on my keyboard will turn on but the caps and num lock don’t work so that tells me that it’s not truly on.. all lights work on the pc and fans work too.. I’ve tried removing the CMOS battery, I’ve tried plugging things in different spots/hdmi spaces, I’ve tried removing the RAM card thing (I think that’s what it’s called) and I have no idea how to fix this.

The background story is that I was playing a game on my gaming computer (cyber power PC) and my friend was playing his Xbox next to me with his little tv too. Story is when my friend left he unplugged his console from the power outlet in my house, as soon as he unplugged it the monitor went black and everything stopped working except the computer itself.. ever since then nothing has worked.. help?