I don't understand why you add the first part of #4. Are you suggesting they replace the fan? You should at the very least suggest somewhere that they put it back on, lol.

You should also know that there are many fan/heatsink (that's what you are talking bout when you say 'aluminum casing') combinations that can't be separated until you take BOTH off. you can't take the fan off of mine without removing the heatsink from the processor.

In that step you've added an iffy situation. If something were to get on the processor or the back of the heatsink, or if they clean it with some sort of dodgy chemical, etc., they could do great harm. Also, there is sometimes a compound there that helps the transfer of heat that should be replaced if it is scraped away, dried out, etc.

If there were to be a lot of air pockets in the old or newly replaced compound, if I am not mistaken, the heat can build up there, and again do great harm. Keeping the case clean inside is very important, and I'd suggest replacing fans a lot more often than people do, but you want to be careful removing the heat sink unless you take care and read up a bit first.

Umm, replacing the fan was said in num. 6. And I did not say 'take off the heat sink'. I just said take all the dust off of the cooling system.

And I don't mean 'buying a new fan', I meant puting it back on.

There may or may not be a consideration of static buildup with a vacuum cleaner, with the moving air/dust thru the pickup tube charging the outer tube surface, to release a healthy zap to a component that doesn't take kindly to static. I use a small air compressor, at a healthy distance so it doesn't put out a strong airstream, but more than the weak "spray can" variety. The nooks and crannies get the spray can treatment, with constant ground-checking and use of grounding-strap to satisfy my paranoia.
Thanks for the reminder, enigma. I'm way overdue!     
And Baker Street: Yes! I pasted the heatsink on my processor three years ago or more when I first built the thing, added the fan, and ne'er the gizmo gets disassembled, ever. No need, for me.

Nice guide! People should open the computer sometimes if it's overheating or not to clean the case for dust.

Using a ground strap is a good idea but if you don't have one just taking hold of the metal frame is enough to maintain a good ground. And if you do remove the heat sink/cpu fan combo (some computers have them) always clean off the old heat sink compound and put a fresh coat on to avoid said air pockets. Also be sure both intake and output fans are free of dust. You may also want to clean off any dust on the motherboard but be careful. Electrostatic discharge can fry your bios chip in a heart beat.

Note that this is a 5 year old thread.

oops. Sorry. I didn't notice ... again.

bakerstreet .... I wonder where he is these days.....

My thoughts too, Paul, when I saw this thread yesterday.

He (too) must have joined real-life(tm) - and gotten a life......