My computer all of a sudden starts making a very irritating loud noise. Could it be the fan which is working overtime? I read the article about the different processors and over heating. I have an AMD K6. I did have an extra 40GB Maxtor hard drive installed. The noise starts with a kind of revving up to a pitch which lasts for a while and then eventually seems to die down! I am worried that if I leave this it could cause a major problem.Your help would be much appreciated.