My computer is making loud sounds coming from the hardware?

I was wondering if this could be the cooling fan needs replacing? I constantly use the air duster to clean it all out. I heard I can take it to like best buy and have it replaced or cleaned out. .is this true? Any help would help a bunch as I haven't a clue on this. .It is silent sometimes and sometimes its really loud machine run sounding. I've only had my HP for a year and a half and didn't purchase insurance on it.