The three elements that play a major role in the stable operation of a computer, are its Motherboard, its memory and most importantly its power supply.
When assembling a computer, the average computer user is more likely to pay more attention to the role of the motherboard and memory in the stability of the computer, while many consumers are ignorant of the importance of selecting a good power supply. Novice computer users mostly use brandless supplies that come with the case, yet many users do not know that the design of such power supplies does not conform to standard power supplies, which may well result in reduced performance and unstable operation of the computer and cause damage to computer peripherals!
Electronic components are affected differently by the different designs of supplies. Therefore, in case of any slight problem occurring when the power supply is transforming utility power (AC current) into +3.3V, +5V, +12V current useable by the computer, the power supply may not be able to operate normally. Or, in case of poor design of the power supply, under certain circumstances it may result in an unstable electric current and insufficient power supply. The computer may seem to operate normally, but in reality the life-span of peripherals is gradually shortened. Therefore, when assembling or purchasing a computer, it is advisable to choose a power supply with a good reputation for quality and to avoid those power supplies that come with the computer case, unless of course you can be sure of the quality of that particular product!