Considering some important components in a computer system and at the same time one of the least respected - probably because of the huge number of very cheap and poorly made Chinese computer cases that come bundled with PSUs - is the power source unit, also known as the PSU. Many problems may arise if a poor quality or an old PSU decides to take a vacation or simply work at reduced efficiency. There are a number of symptoms that detected early can spare the average computer user a lot of grief and lost time and data. For one thing a failing PSU may leak an overvoltage spike that could fry just about every electronic component inside your PC.
If you can hear unusual noises coming from inside the PSU can mean a number of things: this could be dirty or it could be crawling through its last remaining days, hours or minutes. If the PSU is actually dirty, this can be easily fixed with a can of compressed air. Just blow out all the dust from the PSU and try to see if there are any improvements. Most computer parts are very picky about their desired voltage and amperage, a normal PSU must be able to deliver to each component exactly the needed power, too much or too less could permanently damage the hardware.
The symptoms of an old or terribly dirty power supply unit are that the cooling fan or fans are filled with dust, they are very noisy and are functioning at a reduced speed. If this came with your PSU’s cooling fan, then you can either clean or replace the damaged fan, or if the entire PSU is old, a trip to your favorite hardware supplier may be in order.