Still there is no exact document which can guide you the most possible causes of an power supply failure. In a system there are number hardware that rely on the power supply. Especially your hard drive and graphic card. If you do not provide a proper fuel then those can be easily damage. You will need to check properly all the possible causes of a smps failure. Today there are higher capacity power supply provided in the market for desktop computer. Like you can go from 250w to above 1000w as per your need. And even after introduction of technology like overclocking, liquid cooling came into existence. This is an term which provides cool air inside the system cabinet directory to the cpu and graphic cards. This is one of the most costliest cooling technology today in market.
But for regular users there is really not a need for getting an liquid cooling solution. Your regular power supply more than 240w is more than enough for your daily works, games and multimedia files. All you need is to take a proper care and find out the exact cause of failure. This leds you to take some necessary precaution before getting a crash. With the help of some simple tools it is quiet easy to find a solution for failed psu. The regular psu are not so costly. You can just replace that after failure and repair is also cheap. First after a couple of months try to open your cpu case only if that does not void your warranty, and wipe out all the dust. Check the cables and see all are properly connected. This is just an basic housekeeping which avoid major damages in future.
The power supply is dead when your system does not start at all. Now power in the cabinet. You can open up and check the cables. Do not try to replug all several times as it can broke the sensitive pints over motherboard. So do only if you are aware. Sometime a faulty power switch is the reason. There is no power supply failure but it is the power switch which does not respond on click. You need some tools and soldering stuff to fix the same. Just two proper wires and done. There are some power supply tester which can directly guide you to provide info that the psu is live or dead.
The first way to find this out is by getting a burn smell from the cabinet. This happens when the capacitor is blown. At that do not go for anything. Just change it and get a new one. It is not right to say that psu works longer time and they are not fragile. They gets easily damaged by shock, improper electric current and dust. So you must keep a proper eye on them as also along with your other hardware. The power supply inside your computer is responsible to convert AC to DC inside your system. Below are some tips and updates that are needed for you to check and protect your system form getting damage.
1. First you must protect your system from a sudden power failure. This is the first cause of hard drive damage, dead cpu and power supply failure. For those who has this regular must use an ups as an additonal support for the system. So in case if there is a fluctuation the system does not goes off suddenly and preventing from direct impact over the system hardware.1
2. Some power supply fails due to the limitation of their life. That means some psu are just meant to work for some years only. So if you have a old enough psu you can just go and change the same. Dust and smoke is the another cause of psu failure. Dust accumulates space on the board of psu causing the capacitor to blow and this become much more effective if there is moisture in the environment. A another common cause of psu failure is overheating of your system. In systems like overclocking, or some other heavy processing work there is a maximum power drawn by the cpu and other system hardware. This leds to overheating of your system and even has a major impact over the power supply. It can blow off just in some couple of minutes. So it is recommended that you must use a high voltage power supply if you are using more processing power.
3. Sometime you might have noticed in some systems that a working computer suddenly turns off in between or reboots. There are two causes for this. The first one is lies with the power supply which stops working in between. You can test the system by changing the power supply. Second is the motherbaord failure. This is a common issue for an old motherboard.
4. If you want that your powersupply works in your system for an longer time then you must work in the limit of energy consumed by the system. If you are using your system for gaming or for othe purpose then you must use a more than 700watts power supply or else less than that is enough. So when there is high consumption needed for the psu the same is provided by the smps.