It won't boot after power flick

[georgepie]

Hello,

mini tower system has been working for months. This morning there was a power outage of less than 1 second.
After that it doesn't boot. Only the mobo light on.
Tried with a spare (brand new) power supply -connected only the main connector and the 4 pin- result was exactly the same.
What should be the next step?

Thank you

 

[georgepie]

Problem is gone... something strange happened. After the stuff I tried earlier , I also tried the paper clip short to see if the PSU was good. It was.
Then -just in case- I replaced the connectors and gave the system a go.
It started normally. Can only hope that it was a once in a lifetime incident.