I'm with xrobwx71 on this. A vacuum is my least desired way to clean out dust because air and dust particles banging into the nozzle as they zip by can build up tremendous potentials (1000s, even 10s of 1000s of volts!) of static electricity that then can discharge from the nozzle tip through ESD (electro-static discharge) sensitive devices. And sadly, this often happens with we (as humans) not seeing, hearing, or feeling that a static discharge (spark/arc) even happened.
Are you sure all three computers worked properly before attempting to clean? Having 3 suddenly fail at the same time seems unlikely - except through misuse/abuse (and that would include failing to take necessary ESD prevention precautions).
Why was RAM removed from Machine A?
Were the machines unplugged from the wall BEFORE attempting to clean (and before removing the RAM)?
In the future, it is always best to clean out dust by using some sort of compressed dusting gas (commonly called "canned air" though it is not "air" at all, but actually hazardous difluoroethane or a similar gas). Or my preferred method, an air compressor that is properly filtered with an
inline moisture and particulate filter. Just make sure you hold fans stationary to avoid over-spinning them and ruining their bearings. I stick a wooden glue/Popsicle stick in the blades.
And take the computers outside first. No need to blast all that dust back into the room where it can get into your lungs, or where the computer fans will suck it back into the computers.
The only time I use a vacuum is when it is pouring down rain outside. And then I recommend you go by the following procedures:
- Unplug the computer from the wall.
- Touch bare metal of the case interior BEFORE reaching in to discharge any static in your body, and most importantly, to put you and the computer "at the same potential".
- Wrap your hand around the nozzle end and extend a pointed finger out past the nozzle.
- Plant extended finger on to bare metal of the case interior when reaching in with the nozzle to prevent build-up, and then discharge of static.
- Use a clean, soft, natural bristle (not synthetic) dusting or paint brush to gently persuade the dust towards the nozzle.
- Keep that finger planted, and immediately replant it onto bare metal when re-positioning the nozzle.
- Better yet, wait for it to stop raining, then use an air compressor or cans of dusting gas.
I don't see how a surge from the vacuum could do this unless the computers were still plugged into the wall outlet. Remember, for PCs, if the computer is plugged into the wall (and if equipped the master power switch is still set to | or "on"), the computer is not really "Off". It is still in standby mode even when shutdown and +5Vsb standby voltages are being distributed to multiple points across the motherboard.
I will accept Gremlins before a surge (if the computers were unplugged). HOWEVER, because it is unlikely even Gremlins would take out 3 computers at the same time, I suspect user error as the most likely cause.
But I would verify if the computer actually were fully functional before cleaning, or not.
