So my dad turned off his computer sometime around the evening yesterday. We went to turn it on this morning and it won't. No post, no fans, nothing. The power supply light is solid green (it's a 6-year-old HP) but when I press the power button, nothing happens. I reseated the RAM and GPU. Is it the motherboard? If so, I'll just get him a new computer. He's long overdue anyways.