PC wont boot.motherboard or psu?

Vinkor

Commendable
Sep 14, 2016
4
0
1,510
so this happened 2 weeks ago. my pc suddenly won't boot. lights turns on fans spins then shuts off again after a few seconds,fans and lights turns on again only to shut off again. i tried everything that i could google search : remove and clean RAM,then put back RAM. remove GPU.use on board GPU,remove HDD,reset BIOS. I also cleaned everything.removed everything then putback together. i applied new thermal paste,reset BIOS one more time to no avail. i left it alone for a few days then decided to work on it again this time to my surprise the leds and the fan stayed on but wont boot. so i removedvthe GPU again and used the onboard GPU. i was able to get to the BIOS,corrected the time and date and was full of hope.i saved the changes then restarted,i got BOOT MGR IS MISSING so i tot i plugged in my additional HDD by mistake so i swaped it i got the launch windows repair screen or start normally so i selected the repair then Im back to square one. pc wont boot. fans spins leds turns on,few seconds everything shuts off then if i leave it plugged in to the power,it will do the same loop over and over. fans spins leds turns on. shuts off about a few seconds sometimes minutes,it will turn on again.somtimes i will see the windows start up repair only to shut off again.

heres the specs
intelcore i3 quadcore
asus amd r7 260x
ECS h77h-2 m3
gskill 4gb ddr3
cooler master 500w

i dont know which hardware is the problem and i dont have any spares.
i dont trust the repair shops here in my place.im hoping someone can help me or can suggest which hardware i need to replace. thanks
 

Vinkor

Commendable
Sep 14, 2016
4
0
1,510
This is an update. I installed a new psu driving force 600w it runs for a few minutes but still shutting down. Im on my onboard gpu since the psu that i purchashed doesnt have the 6 pin for the gpu.i cant update tbe onboard gpu driver since its shuttjng down. I cant read the event log as well