I have an issue with my PC, sometimes it will turn on but nothing else will turn on.

[tom15]

I have an issue with my PC, sometimes it will turn on but nothing else will turn on. I will click the power button and the indicator light will turn on but the 2 Monitors, Keyboard and Mouse fill fail to turn on. So far have replaced the Motherboard, PSU and CPU but problem still persists, possibly a POST fail? Could be GPU, SSD or 2nd HDD. Help is greatly apreciated. This problem isnt detrimental to my PC but dont want it to escalate. I can fix the issue by turning off the PC and switching it back on again and works fine.

 

[AMD Radeon]

Complete list of troubleshooting, in case you need it
http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems