An indication of no power is if you press the computer power button and you see no lights or any activity. You’ll need to check if there is power from the power source, such as the wall outlet that your computer is plugged into? Check if there is power coming from the power supply. Use your multimeter to test the AC power fron the outlet and the DC power coming from the power supply in the inside of your computer.
Consider if there may be insufficient wattage from the power supply unit. If you’ve just installed new components, such as a high end graphics card, the new component may draw power above which the PSU can provide.
