Is you computer refusing to Switch ON or crashes and freezes apparently for no reason? Then your computer may have Problems in Power Supply.
A Power Supply Unit or Switch Mode Power Supply(SMPS) converts the A.C. to lower D.C. voltage for use of internal components of the computer. If your Power Supply is unable to provide the required voltage to the computer components, it may freeze, crash and restart for no reason.
Methods to the Power Supply Problems.
Method 1: If your computer is refusing to start, then checking your Power Supply using Multimeter is a good place to start. Check How To Start your Power Supply Without a Mother Board for starting your Power Supply without a motherboard.
If your Power Supply starts without your motherboard, then Power Supply holds good and you need to check How to Troubleshoot computer that does not turn ON for other components of the computer.
Method 2: If your computer is facing frequent restarts, crashes or freeze, then you need to check the voltage provided by the power supply. Check Power Supply testing with a Multimeter for checking the voltage provided by power supply using the multimeter.
If your Power Supply is providing the required voltage under load, then check Troubleshooting computer that Freezes for reason.