Screen Flickered Once - PC made strange hissing / whining noise after

[Fina1]

UPDATE : I realized the noise is actually coming from the speakers, which are plugged into the monitor USB. By turning off the monitor, the speakers also turned off, so the noise stopped. But changing the volume of the speakers changed the noise.

So I was using my less than 2 weeks old PC, when suddenly the screen flickered once while I was printing a document (not my first time to print one).

All parts are completely new. I am using the ASUS 27" G-sync monitor.

Immediately after it flickered, I heard a strange whining / hissing sound from the PC. The sound was not constantly the same but changed to about 4 or 5 different sounds over the course of about 1 minute or less. It sounded like the faint sound came from the PC and not the monitor, but it was over pretty quickly I didn't have a chance to check each carefully.

Then the noise went away completely. Everything seems to be working fine. Temperatures have been all fine and even modern games on Ultra settings, the CPU or GPU never go above 70.

What caused the sound (monitor or CPU component)? Why did it come and go so quickly? Should I be worried?

I also have an SSD, so I don't think it was a hard drive component.

 

[ffg7]

more likely it was the psu that made that noise or the motherboard itself. how long is your warranty good for? are you using a surge protected powerbar?

 

[Fina1]

The warranty is for 3 or 5 years. I forget which one. It's Corsair RM 850.

I am not using a surge protector. I had asked on another forum if I should get one, and everyone said "you don't need one". I guess they were wrong.

I will go buy one today.