Gaming PC making noise when off

[Confused_Panda]

Hello this is my first time posting a question like this  here so I hope I will get the help I need. So basically I have had this HP Pavilion Gaming desktop for about 1 year now when I first bought it there were no noises when I used to turn it off or at least I did not notice it. But after sometime when I turned off the PC there is this buzzing type of noise coming from the PC. It's not like loud loud and you can only hear it when you listen closely to it by standing near it. I have ignored this the whole time and still do because my PC works fine I have no issues with the PC itself. Everything runs like it should, but I am just curious if this noise should be a concern or not. But so far I have had no issues for the whole year, so just want to know what this is. Thanks 

[GamingOptional]

Unfortunately the only way to answer your question is with a physical inspection, listening to the noise, checking the internal connections, using a multimeter to check for correct output, etc.

A quiet buzzing sound isn't much to go on without knowing where exactly the buzzing is coming from.

If you are not inclined to take it to a local shop or send it to HP to have it looked at I would guide you to the link below since you've been running the PC for a year:

HP PC Spring Cleaning