Hello, I HAVE A ASUS P5N-D MOTHERBOARD AND IT SHUTS OFF ITSELF AFTER THE FIRST 10 SECOND AFTER TURNING ON.... SOMETIMES IT WORKS FINE, BUT WHEN LESS YOU EXPECT, IT BEGIN TO SHUT OFF.
Hello and welcome to the forums
Like dj1997 said,it could be an overheating problem so re-seat your CPU/heatsink, also make sure your heatsink has adequate thermal paste on it.