Pc crashing help

[Miles_13]

The past few days my pc would randomly shut down with no warning, no bsod, no nothing. 5-10 seconds after it shut down it would restart automatically. Today it shut down but this time when it restarted my monitor stayed black but the pc was on. After looking in at my house I noticed the fans would spin for a few seconds then stop over and over. So is this a you or psu problem? Also, if it matters non of my usb devices turned on

 

[bvanevery]

Do you have any reason to believe that your electrical grid in your geographic area suffers brownouts ?