If your desktop computer makes a squeaking/whining sound when it is powered off, it could be your power supply still being on even though it should be off.
Fixing squeaking and whining sound from your computer after shutting it down can be as simple as unplugging your computer from the wall’s power outlet for a few seconds, and plugging it back in after you don’t hear the squeaking and whining sound. But, you’ll probably hear the sound the next time you startup and shutdown your computer.
I notice squeaking and whining sound from a computer happens mostly on computers which are many years old like ten years old.
I permanently fix my older desktop computer which makes squeaking and whining when powered off from clicking on shutdown on shutdown menu in Windows Start menu by replacing the power supply with a newer and better power supply like the Cooler Master Elite Power 460W Power Supply .
In my experience, desktop computer power supplies tend to make whining sounds after many years of constant use for hours a day because of wear and tear from constant usage, and aging parts which maybe failing. It is a good idea to replace a power supply if it is making weird noises when powered on, and off because something maybe slowly breaking. When a power supply breaks, it can destroy your entire computer by frying the motherboard, RAM, CPU, video card, hard drives, optical drives, and expansion cards with too much electricity.
The power supply on my older desktop also made weird electricity sounds when power on. A power supply should only have the sound of the fans running if it is fan cooled power supply. On fanless power supply, it should be silent like other devices like the power adapters for laptop which are fanless, and rely on the surrounding air to cool it.
Replacing the power supply is not hard to do. There are a lot of online tutorial videos and blog posts on PC Help websites for learning how to install power supplies on computers. All you need is a cross head Philips screwdriver to unscrew the power supply, so you can remove it. Make sure to unplug your PC from the wall’s power outlet.
After you unplug all the power cables, and other cables like video, sound, USB cables, etc from the back of the PC, you need to open your PC case to unplug the power cables coming out of the power supply which are connected to your hard drive, motherboard, optical drives, fans, and other parts.
When you remove the old power supply, you need to install the new power supply by screwing it into your case, and plugging in power cables from the power supply into your hard drive, motherboard, optical disc drives, and other parts. Lastly, plug in your power supply’s power cable, and turn on your PC to test if you installed it on right. If you did, your computer will turn on, and startup into Windows, or another operating system like Ubuntu Linux which is installed on your PC’s hard drive. You don’t need to install any additional software like hardware drivers to use your power supply. Lastly, shutdown your computer, and screw your case door back on your PC case to protect it from dust, dirt, and junk.
Power supplies for desktop ATX Tower PCs are very affordable compared to other computer parts like a CPU, you can get a good power supply for under $40 like the Cooler Master Elite Power 460W Power Supply which works with 20 and 24 pin motherboards.
Installing a new power supply can improve cooling for your computer because many power supply these days come with big fans which spin slowly, so they don’t add much additional noise to your computer while cooling it. Some power supplies also come with better cable management, so the cables, are not blocking air vents on your computer case, and fans, so your computer runs cooler, and more quieter because your other fans don’t need to spin as fast to cool your PC to prevent overheating.
A new power supplies can also improve the appearance of your desktop PC because some of them have nice back grills and nicer fan grills which gives both the inside and outside of your PC a cool modern look. Some even have blue LED lights in it to give your PC a cool SCI-Fi look which is great if your PC Case has air vents, or a Clear plastic Window where you can see inside the case, and show off your computer parts.
The most common power supply for older desktop computers made in the year 2000 and up is the ATX 20 pin power supply for desktop computers.
There are newer 24 pin power supplies which work on 20 pin power supplies because the 4 extra pins are detachable making it a 20 pin power supply which would work on older desktop PCs.
If you replace your power supply, and still hear a whining and squeaking sound after you shutdown your computer, it could be your motherboard, or an expansion card like a video card, sound card, etc which is causing the whining and squeaking sound.
Fixing weird electricity sounds like whining, squeaking, and whistling can be as simple as unplugging it from the wall after shutdown, but a more permanent way to fix the sound is to replace the power supply, or other part which is causing the weird sounds when your desktop computer is shutdown, and power off.