[SOLVED] What is making this sound ?

[Finket]

When I shut my computer off it makes like a screech that was quick and semi-loud so I turned my computer on again waited a bit everything was running fine so I shut it off again and it made that screech again. Earlier today I opened my computer and and dusted it. I have an Alienware aurora r11 so I had to pull the psu arm out and I didn’t bend anything so I have no idea what this could be. It is not effecting the performance or anything. Can somone please help ?

 

[helpstar]

Maybe the pump liquid got a view bubbles in between while the case was lying on the side. Was the case upside or on the side while you turned it on and off?
Run it upside around an hour and the bubbles should be on the correct place again

Does this system have an ODD drive (DVD/CD)?

Check the tubes of the water cooling if squeezed or similar