Right, here goes, I'll try and explain slowly how I clean the 25 machines I run at work (and have done for the last five years)-
*Take the side panel off.
*Hold the vacuum cleaner nozzle just inside the case at the bottom - it will be at least 50mm away from any of the components.
*Use the soft bristled paintbrush to lift the dirt off the motherboard, fans etc. The soft bristles cannot possibly do any damage to anything provided a reasonable amount of care is taken.
*Most if not all the dust gets lifted away into the nozzle.
Why do I use this method? Compressed air just stirs the dust up - its mostly dead skin cells and body hair btw so not particularly healthy to breathe in. And it has to settle somewhere again, probably inside the computer case. Also, aerosol cans are expensive and environmentally unfriendly even if the propellant is inert. A properly earthed vacuum cleaner should not generate a high static charge, and anyway if you're inside a computer you should be wearing an earthing wrist strap. If you get a spark off a metal hose attachment its likely that the vacuum cleaner itself has an earth fault.
The liklihood of sucking a soldered component off the motherboard is zero - unless you're a gorilla. If you don't feel happy doing a job like this you probably shouldn't have taken the machine apart in the first place.
