PC shuts down and restarts

[kyd15]

PC shuts down at startup and restart automatically in few seconds
This doesn't happen oftenly but i could experience this once in a week.

PC attempts to start but no display though all components seems to be working. After 4-5 seconds it shuts down and then restarts automatically and everything works normal after that.
Is this a symptom of a PSU/Mobo failure? My PC is over 5 years in age and I never had serious issues with it.

Intel core i5 3470 3.2Ghz
G.skill 4GB ddr3
Gigabyte h77-ds3h
Gigabyte gt 730 2gb gddr5
Hitachi 500gb
Inwin c638 case + inwin 400w PSU

 

[Rogue Leader]

Memory errors can cause that, so lets go the cheap route here and download memtest86 and run a memory test for a few hours see if anything pops up.

 

[kyd15]

Memory errors can cause that, so lets go the cheap route here and download memtest86 and run a memory test for a few hours see if anything pops up.

I ran it once and stopped it after passing a single round although you should atleast complete 7 rounds. I'll try to run a complete test.

 

[Rogue Leader]

Memory errors can cause that, so lets go the cheap route here and download memtest86 and run a memory test for a few hours see if anything pops up.

I ran it once and stopped it after passing a single round although I've you should atleast complete 7 rounds

Yeah you need to run it for a while. Try that first, lets eliminate that possibility.