[SOLVED] 5-year-old Prebuilt Dell Computer Making Strange New Noise

[help4whistling]

My 8700 XPS computer has started making a strange whistling noise with a gradually-ascending pitch that lasts for maybe 6 seconds. I first noticed this a couple weeks ago. I hope I listed this in the right forum, since I don't actually know which component is causing this.

The sound happens maybe every half hour or so, but it can vary. It happens even when I'm not doing anything/components aren't under any strain whatsoever. My specs are:
Intel Core i7-4790 CPU @ 3.60 GHz
8 GB System RAM
Nvidia Geforce GT 720 graphics card
64-bit operating system
Windows 10
460 Watt PSU

 

[Bassplate]

Good day!
May i know what motherboard you have installed?
And do you have other system fans build in inside your casing?

 

[help4whistling]

Hello! I have a 0KWVT8 Version A03 motherboard. I hope that's the information you were asking for. It's what came with the computer. Also, I have an exhaust fan on the back of my case. (also came with the computer...I haven't made any modifications to this PC)

 

[Bassplate]

Thank you Help4Whistling
Well firstly let me ask this:
When the whistling noise appear...does your computer freezes or does it restart/shutown unexpectedly?
The whistling noise i think can come from some sort of fan maybe that there could be something stuck in the fans fins or in the bearings.Well there are some things you can try yourself to see where this whistling noise comes from.
1.Try removing the system fans EXCEPT YOUR CPU FAN,just to make sure if its not maybe the fan itself thats causing this noise.Try removing them one by one to know which fan maybe the one causing the noise.
2.Try cleaning your fans....all of them including your cpu fan.
3.If its not the fan...check your Power Supply fan,sometimes the Power Supply fan can make trouble and could cause some other components to having trouble functioning.Like fans or stuff.
4.Something simple...Open up your side panel of the computer then stick your head in it and power up the system.Then you must pay close attention where this whistling noise are coming from....NOTE IT COULD BE YOUR HARDRIVE AS WELL that could makes strange noises.But we hope thats not the situation.
Try it and let us know if you found where the whistling noise are coming from.

 

[help4whistling]

Alright! Sorry it's taken me so long to get back to you, but I got things troubleshooted...troubleshot? Anyway. My computer doesn't react unusually at all when the whistling sound occurs. I tried to remove my one system fan from my computer, but the noise still occurred.
I've also dusted inside my computer, including fans, although I couldn't fully reach the PSU fan without tilting the canned air too much, so I left that imperfectly dusted. I listened carefully while the case was off, and I'm almost certain now that the sound is coming from my PSU, which seems...bad. So I'm guessing I need to buy and install a new one? Also, thanks so much for all your help!!