Okay For desktop is computer is not turning on. So first we have to check the power and if power is not coming then we First we have to Swap the power cord check the another which is working and if the power is fine first we have to If the system is not getting on I mean just we have to just tag check the CPU CPU and motherboard CPU Powers first sorry, we have to check the power supply and there are two wires and The green or Black wire we have to just sort out if it is the power supply the okay, then we have to Check the next step the motherboard is getting the power or not If there is any beep sound or indication, we have to clean the motherboard with a virus and the Completely and we can we can DSM the completely CPU and minimum component Requirement the motherboard is going on then some time due to the dust or such issue the system is System does not get open does not on so that is the reason in this way first, we have to check the power supply power cord and The power Switch is a light coming or not electricity is coming or not and second power Cords check swap the power charge if power or is okay, then check the power supply then motherboard also if there are two Power supply is okay. The motherboard is faulty if power supply is not okay, then we have to replace the power supply Thank you in this way we can Diagnose the system. Thank you