PC started to smoke after CPU install

I had removed the CPU from my pc, it was working fine before I removed it. When I reinstalled it and booted it up, however, the pc power light and diagnostic lights all shut off, but the hard drive light and fans were still on, like if the pc was half off, and I couldn't shut it down through the power button. Since the cover was off, I managed to smell a little bit of smoke. I immediately unplugged the pc once I smelled the smoke. When I looked with a flashlight, there were no signs of damage or burning on the motherboard. I traced the smell, which didn't go away, and figured out it had came from the power supply. I couldn't see any burnt components, but the fan was really dusty, so that could be the issue. Please let me know if you had any suggestions.