DOA

Something happened to my computer. I came home one day and everything was fucked up on the desktop (fonts, icons, etc.) and there was an error message about Power Management failed to install correctly. Everything functioned properly, but I couldn't figure out how to fix it. I tried relogging in and restarting the computer, but that didn't fix anything. Then yesterday I tried a cold reboot, except the "boot" part doesn't work anymore. So either something is wrong with the power supply or the motherboard is fried. I'm hoping it's just the power supply, because that's the easy (and cheaper) fix. My power supply has an extra plug that is supposed to provide stable "cleaner" power to the motherboard, so maybe that part failed, which is why my computer initially continued to operate.