My old computer is really weird its about 5 years old. When you turn the computer off, from the OS, it shuts down but the fans are still running quietly, all of them(cpu, case, video), u have to manually switch the
power supply off for the fans to stop running. When i start the power supply back on the fans run quietly and I would have to press the case power button on for it to start fully. But it still gay, when i do try to turn it on sometimes it wont load to the OS, sometimes its just black, and others its the blue screen. Im not sure what the problem is, im formatting my computer if it will help anything, if so ill tell u.