It started yesterday. Extremely loud noise... sounding something like mixer or like drill. I mean not identical, heh, just this sound makes me think of these. Like something's spinning. Yesterday sound was constant. Today morning I opened the case and removed as much dust as I could handle although I'm not 100% sure I got rid of enough of it. So when I turned it on today at first sound was gone (yay) but then it appeared again, as loud as yesterday. After a longer while it became quieter and eventually disappeared again. I had some moments (long enough to wonder that maybe I fixed it) of silence and then it started again. Now it comes and goes.
What I could do about it? Am I even on right track? Maybe cleaning it helped but maybe I missed some dust and I need to try again? Or just some fan is dying and I need to replace it? But cleaning helped so maybe it's really just dust?
Don't ask me which part of computer it is because I don't have a clue... it's so loud that I can't really tell. It feels like this sound is everywhere, it took me a while to even realize that it's computer.