There is something seriously wrong there?
What are the makes and models of the power supply and the motherboard?
Which components are installed on the motherboard when that happens?
You should have a minimum of the memory modules, video card, and processor with its heatsink and fan installed.
You should not power up a motherboard if it has no load.
Have you checked to make sure that the voltage switch on the power supply is switched to the correct voltage for your country?
In the UK it is 230V and in the US it is 115V.
Failure to ensure this switch is set to the correct voltage will probably destroy your PSU.