Hello, I have an Acer 5920-6727 and the fan makes a loud screech/shriek! I've opened up the back and cleaned out the laptop the best I could, but it still makes the sound. Maybe more now than before. I don't know what the problem is. Any suggestions?
see first if there isn't any wire touching the cooler of if the cooler isn't touching the case;
otherwise, sometimes the cooler get a little (off aligment) so it start spinning unperfectly, the solution is to change the specific cooler for another one.