The Power Supply Unit (PSU) is the heart of your computer.
It converts the high-voltage alternating current (AC) from your wall outlet into the clean, low-voltage direct current (DC) that your components need.
Yet, it’s often the most overlooked component in a build.
A failing PSU doesn’t just stop working; it can unstable your entire system or, worse, destroy other components like your CPU or GPU.
If your computer is acting strangely, here are three clear signs that your PSU is on its way out in 2026.
1. Random Restarts, Freezes, or Blue Screens (BSOD)
One of the most frustrating symptoms of a dying PSU is random instability.
If your PC restarts without warning, often when you’re doing something demanding like gaming or video editing, the PSU might not be able to provide a stable flow of power.
These sudden power drops cause the CPU to shut down as a safety measure.
2. Loud Noises and “Coil Whine”
Your PSU should be relatively quiet. If you start hearing a loud grinding or rattling noise, the internal fan is likely failing, which will lead to overheating.
Another auditory sign is “coil whine”, a high-pitched squealing or buzzing sound.
While some coil whine is normal under load, a sudden increase in volume can indicate that the internal electrical components (capacitors and inductors) are stressed and failing.
3. The PC Simply Refuses to Turn On (or needs a “trick”)
The most obvious sign is when you press the power button and nothing happens.
No lights, no fans, just silence.
However, a common precursor to total failure is when the PC needs a “trick” to wake up.
As we detailed in our guide on troubleshooting a PC that won’t turn on, if you need to unplug the power cord for 30 seconds before it will start, your PSU is failing to discharge properly and must be replaced immediately.
Don’t wait for a total catastrophic failure. A bad PSU can send a power surge that could ruin your SSD. Make sure you regularly check your SSD health if your system has been experiencing power-related instability.