Question Motherboard not power on at sometime

[Harshana_Leel]

Gigabyte z77 UD3H MoBo not turn on at sometimes.
But it is working properly. It just not turn on sometimes. Fan spinning for few seconds then reboot continuously. Any reason or suggestion to fix this please.

 

[Lutfij]

When posting a thread of troubleshooting nature, it's customary to include your full system's specs. Please list them like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:

Please include the age of the PSU apart from it's make and model. Side note, what BIOS version are you on for your motherboard?