You will be using compressed air and a vacuum to remove the majority of the dust from the inside of your computer, so set up an area that you can blow dust out without worrying about getting other things dirty. A garage or workbench is a good choice, or you can go outside if it's a dry day. Try to set up a table so that you can easily access the computer without having to bend over or set it on the ground. You will need a Phillips screwdriver, compressed air (either in a can or via a compressor), a small vacuum that can fit in narrow crevices, a toothbrush, and 99% isopropyl alcohol.  Do not use an old vacuum with a metal tip, as these are usually poorly grounded and can damage your components. The best option is a newer handheld vacuum with an extendable plastic hose. The toothbrush should have soft bristles, and should be new. Shut down your computer and disconnect all of the cables on the back. Make sure that the monitor is unplugged, and that any USB cables, Ethernet cables, speaker cables, or anything else is unplugged as well. Flip the switch on the power supply and then remove the power cable. Place the computer on its side on your table or workbench. Make sure that the connectors on the back are laying closest to the surface. These connectors are attached to the motherboard, and can help you ensure that you remove the correct side panel. Remove the screws that hold the side panel in place. These screws can be found along the back of the computer. Most modern cases have thumbscrews that you can remove without tools, though you may need to use the screwdriver for older cases or thumbscrews that are too tight. Set the screws aside so that you don't lose them. Depending on how long it's been and your environment, you could be greeted by a pretty gruesome sight. Dust has a tendency to collect and cake on your components, and the entire inside may be covered in a fine layer of gray. Use your vacuum cleaner to do a pass over the interior, sucking up the large bits of dust from the components and crevices. Be...

TL;DR in Indonesian:
Tentukan tempat untuk meniup debu dari komputer. Kumpulkan peralatan yang dibutuhkan. Matikan komputer dan cabut semua periferal. Baringkan komputer ke sisi sampingnya. Lepaskan panel samping. Lakukan penyedotan awal. Gunakan udara terkompresi untuk meniup debu dari celah-celah. Bersihkan kipas dengan pengisap dan alkohol. Lepaskan komponen untuk pembersihan mendalam. Bersihkan bekas panas.