Won't turn on

[Thi__Thi_]

Hello. I've just build my new PC and when I go to turn it on for a test run, it turns on for a few seconds, then turns off. it does this repetitively. What do I do??

 

[Jasjar]

http://www.tomshardware.com/faq/id-1893016/post-system-boot-video-output-troubleshooting-checklist.html