When the computer makes a "whistle" sound, it signifies that the processor is facing a high temperature issue. This can be due to an overheated capacitor in the CPU which can burn if it is not taken care of. It could also be due to poor CPU fan performance and a lack of ventilation to the hardware components leading to the damage of the CPU. The computer shuts down usually after the "whistle noise" as precautionary measures are used to stop further damage to the computer architecture inside the CPU. In fact, the internal wiring of a CPU due to tangled cables block the fan and spoil the ventilation or make a screeching "whistle noise ".
A computer usually makes a weird "whistle" sound if it has detected a problem with the temperature of your processor. This can come from an overheating issue caused by the absence of, or defect in, the CPU/ power supply fans. If the fans cannot provide sufficient ventilation to your computer's components, this will cause your hardware to overheat and damage the components inside the CPU. Often, your computer will shut down just after this "Whistle" noise to prevent jeopardizing your computer system.
Sometimes, cables from inside your CPU might also be blocking the fan from working properly. They can get stuck in between the fans and be the source of this weird noise.
To solve this issue, follow the steps below:
Step 1: Shut down your computer immediately (if it has not already shut down automatically)
Step 2: Unplug the power supply cable from the CPU and make sure that you have unplugged any devices before unscrewing the CPU cover.
Step 3: Make sure that no cables are obstructing the fans and that the right cables are plugged in the fans.
Step 4: Remove any dust particles that might have accumulated inside the CPU with a compressed air sprayer designed for this task. If you do not have one, you can use a soft paint brush.
Step 5: Without closing the CPU, be very careful while connecting the power cable again. Switch the CPU on to check whether the fans are working properly.
Step 6: If this is not the case, you might need to buy new fans to have a proper ventilation for your CPU ( you may need the help of a technician for this issue)