So this has been happening for some time now and i'm really starting to worry. I built my first PC back in November and one part that i had with it was a Seagate Barracuda 3TB 3.5 inch 7200 RPM Internal Hard Drive. For the past month and a half, i believe, everytime i power on my PC it makes a grinding/rumbling noise and lasts for maybe about 10 seconds or less. The startup process is normal and it is fine so no problems with that. Also i ran diagnostic checks on my hard drive and it says everything is functioning properly. So what i'm wondering is why is it that everytime i start up my computer, my HDD makes that noise for about 10 seconds and then the noise stops?