Computer Repair: The List

Some days we awake to find the humming box in the corner is no longer humming or is making an unhealthy sound you're certain is not humming. These machines are known as desktop computers. They break. They whine. They fry from electrical surges. They short out. They occasionally buzz angrily as cords sway into open fans. They sometimes produce a perpetual void of black screen, and you wonder to yourself whether your documents are still alive and well. They aren't perfect and are often frustrating to repair by the lesser experienced. The purpose of this blog is to help those in need with desktop issues, where booting up the computer is impossible, unstable, or very difficult to accomplish. Every machine's issues I've ever dealt with (and successfully fixed) are now compiled into a very basic and rudimentary list of tasks one should check when the system cannot boot.
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1.) Heatsink is properly attached, therefore fully capable of distributing processor heat. This is critical: If the heatsink shorts the motherboard below it, or is not seated on the processor, the system can't boot. By "shorting," I am implying the electrical term where something metallic (the heatsink) is touching a semiconductor (the motherboard) and the power flowing through the semiconductor is interrupted or directed elsewhere because it also flows through the metallic object. Always ensure your heatsink is made for your processor port, and that any metal is touching the processor, or some sort of nonmetal washer.
2.) Your RAM is a known stable stick, and is compatible with your motherboard. Typical RAM type format (the brackets indicate variables): "[DDR] [#] (PC [#])." Whenever testing RAM, test one stick at a time!
3.) Nothing is shorting the motherboard, whether this be on the front or back side. Screws and other little metallicy stuffs can fall into the space between the motherboard and the metal of the case. Once caught in there, they can produce shorting issues. As mentioned, heatsinks are capable of shorting the motherboard. A very good way to define a destroyed board from one that is merely shorted: Remove the motherboard from the case and set it down on a nonmetal surface (foam is good). You may need to move out your components as well, but the power supply and any video cards are the essentials, just to see if the motherboard can boot up.
4.) Your motherboard is receiving proper power. "Proper" power is produced from a stable power supply, a power supply with a wattage that can power the entire machine, and power from the electrical outlet used is trusted, functional, and not crowded with other power-demanding devices on a power strip/surge protector. Many computers as of today should have 300watt-350watt minimum power supplies to avoid lack of juice. Antec is a well approved manufacturer, as Belkin is, likewise, for power strips.
5.) Your motherboard "appears" healthy. Motherboards create many an issue, as they are sensitive to power and the crucial hub used to transfer data around your system. Apart from testing different components, it's always good to look on your motherboard for anything burnt (the result of current issues, when you overcrowd electronics on one electrical port), typically around the multi-pin power connectors. Other unhealthy signs include the corrosion or "fattening" of capacitors, which are small cylindrical objects found abundantly on the motherboard. Their purpose is to house temporary power. However, if the motherboard is apparently healthy, it doesn't mean there isn't something wrong with it. Power, again, is the culprit in many motherboard murders, where a current or surge issue destroys the board silently. The only repair option is a new motherboard.
6.) Your monitor is functional. The only real way to test a monitor is to use a separate computer on it.