Newly built computer problem

[MK Bren]

I recently helped a friend build a computer from scratch and after building everything there was no video feed at all (tried to plug in both MB and to the Vid card) and the cpu would reboot itself (fans turn off and on) every 4~7 seconds or so. Is there anything that can be done or is either MB CPU RAM defective? I also tried to use just the bare minimum ( MB CPU PSU RAM [tried both sticks] and run it without the case and the same thing happenned.

The parts are the following:
F3 1600 C9D 16GXM (8G X2) RIP JAWS
Z77a gd65 MSI
Intel i5 3570k
CORSAIR Builder Series CX500 500W
SAMSUNG 840 Series MZ-7TD120BW 120GB
Old DVD reader
ASUS Radeon HD 7870 (tried to use it with and without and same result so I assume it's fine)

 

[butremor]

http://www.tomshardware.co.uk/forum/261145-13-perform-steps-posting-boot-video-problems

 

[MK Bren]

http://www.tomshardware.co.uk/forum/261145-13-perform-steps-posting-boot-video-problems

Thanks but I checked that already.... and also it reboots itself every few sec.