• If your computer shuts down for no apparent reason, you may have a power supply problem.computer image by Ewe Degiampietro from Fotolia.com
  
  A computer's power supply is connected to the motherboard and delivers the necessary electrical current from the power cable or battery source to make the computer run properly. Before a power supply fails permanently, it may exhibit telltale signs of a problem. Recognizing these symptoms will give you time to replace the power supply before total failure occurs.
  
  

Random Restarts

• If your computer suddenly shuts down and reboots for no apparent reason, it may be a sign that your power supply is going bad.
  
  Fluctuating power distribution causes these random reboots. Your computer may run normally when the power signal is within the specified parameters. When the malfunctioning power supply drops below the acceptable levels, the computer will sometimes automatically restart. This could corrupt files or systems and cause you to lose unsaved work.
  
  

Non-Functional Power Button

• Most computers power up when you press a single button. However, when you press the power button and nothing happens, there is an immediate concern.
  
  Although a malfunctioning button is possible, the most likely cause is a failing power supply. If the power supply unit has deteriorated to the point that it does not communicate with the motherboard that enough power is available, then the button may be disabled automatically. Also, if the computer appears to start up momentarily and then shuts back down, the power supply may be the culprit.
  
  

Power Failure During Multitasking

• Programs demand different levels of performance from your computer's hardware. For example, watching a high-quality video clip with stereo sound requires more power than reading this page and looking at photos.
  
  Also, the more programs open at once, the more power is needed. If your failing power supply is not able to handle the load, the computer will shut down unexpectedly. If your computer continues to shut down when you have multiple programs running but does not shut down with only simple tasks open, you may need to consider the possibility of a bad power supply.