This has been happening for awhile now but everyday when I first startup the computer it makes this grinding noise that lasts for about two minutes then it goes away and is fine for the rest of the day when I use it. At first I thought it was dust so I took it out and cleaned it up a bit with a can of compressed air. After trying that, the noise is still there. I don't think it's my hard drive since I use a SSD.
I haven't gotten a chance to open the case and carefully listen to where the noise is coming from but one thing I do know is when the noise is happening and I thump the case with my hand a few times it seems like one of the fans inside makes this lower power noise thing and then slowly comes back up to normal. Keep in mind this only happens if I thump or hit the case with my hand. I'm planning on opening the case soon and see what it causing the noise but I'd like an idea if you guys know if what could be causing the noise so I know what to pay attention to. And what can I use so I can hear better where the noise is coming from?
Yeah I had the same issue in my old P4 computer that I still have today. Its my CPU cooler, made a horrible grinding noise for around 5 minutes then quietened down. Just open the side panel of your case and just see where the noise comes from when you turn on the computer.
yeah, it's almost definitely a fan. Hardest part is figuring out which one is making the noise. With the fans inside the case it's difficult to tell where the noise is coming from, easiest way is to unscrew them and lay them out outside the case (including power supply). Should be able to isolate it then. If the noise is still inside the case it's probably a heatsink fan as JJ1217 suggested.
edit: first check to make sure no wires are interfering with any fans (hitting the blades).