Question System Unit is on but Keyboard, Mouse, and Monitor isn't working

Feb 12, 2021
I left my PC idle before I took a bath. Later on, when I came back from bath it shows BSOD: IRQL_ERROR_CODE since I have no time to fix it. I left it for a while because I have errands to do. Now, my Keyboard lights is working but the numlocks won't turn on, mouse isn't working but the sensor light (i don't know what do you call the red light under), Monitor shows no display, and System Unit is on.
Steps I tried:
  1. 30-seconds trick
  2. BIOS reset
  3. Switch Dual 8gb RAM
My guess is it is a power supply problem. But, to be sure I want y'all opinion first.