What kind of HSF are you using? Are you over-clocking? Where is the case located(in a desk)? What is the room temperture? Did you build this system or is store bought? Have you ever been to the Artic Silver Web-site to check out how to apply the Thermal Grease? How many case fans do you have? What kind of P/S do you have? Are you using round IDE cables? What size is your case?
My take on your story: Read all you can on HSF's(Heat Sink Fan)like the reviews on this site and Anandtech, and replace your HSF with the best one for your needs(if you don't like noise read the results vs. noise) and use Artic Silver III thermal grease. If I were you I would use a Vantec 6027D( like $20 USD) or a TI Dr Thermal HSF(like $22 USD), both are decent, fairly quiet & not costly HSF's. I would not use these HSF's for over-clocking............I use a OCZ Goliath..........my GF hates it & it scares my dogs out of the computer room, but it is big, all copper, ugly, beyond loud and most importantly it is the coolest HSF that I have ever used! If you can add more case fans. Oh Yeah, if you are using "Round" IDE cables, try using the flat ribbon cables(less data loss/corruption). Good Luck
WHAT????? I CAN'T HEAR YOU OVER THE ROAR OF MY CASE FANS! YOU'LL HAVE TO SCREAM!