PC not posting but getting power

[ImStylee]

So i built a pc about 3 years ago, and it has been running well till this day, no major issues until tonight when i tried to turn in on and nothing happened, well something happened, it does have power and it gets the fans spinning and its just like its trying to boot but this lasts for one second, after that it shuts down and tries to boot again. I've tried to do everything even what is adviced on this forum, before posting ofc. So what i've managed to do is by removing the cpu powercable the machine stays on but obviously wont boot. After that i tried to clear bios and it worked fine, i had the cpu powercable and motherboard power cable on but it wouldnt boot even with this. Then i restarted the pc and i was back to square one, it was like i never cleared bios. I really dont know what to do, please ask if theres anything unclear

 

CPU:i5-6600k

GPU:1070ti A 8GB

RAM:16Gb Kingston DDR4 2666MHz

PSU:Corsair VS550

[boggy77]

The psu might be the problem. The vs series isn't great