How to remove dust from computer, and make it stay clean

So you are opening your cabinet and you notice all the dust. Surely not any good either for your computer or the fire safety. Here is a quick-step how to on removing it and making your computer stay clean.

Part 1: Remove the dust
Turn of the computer, and take all necessary measures before touching any parts, so you don't short-circuit any parts. Open it up, and remove as much dust as possible. Get yourself a spray can with compressed air to clean your motherboard and other vulnerable parts. Cleaning fans is a bit harder, and you might have to detach them in order to get everything.

Part 2: Making the computer stay clean
What I have found to be a good solution is getting a fan which blows air in with a good particle filter. Either 2x80mm fans blowing at low speed, or a big 120mm fan. This has kept my computer clean for years, although I have to clean the particle filter every now an then.