Hi My computer is shutting off and turning back on, with no bios screen. new build, tried another mobo that was working just two weeks ago, same thing. my new mobo was a Asrock killer z97. all fans come on then shut off, I checked all wires for shorts and proper installation, checked memory, bought a brand new power SUPPLY Consair cx750m. what could cause this? Even a new power supply might do that.
Are you using a SSD? Has it been working prior to this build?
Remove all drives and USB devices, except keyboard.
Reduce memory down to least. TRY an old memory stick.
No then can you get a stable BIOS screen?
What motherboard do you faveNo I am not using an SSD, Seagate 1tb, the mobo I am using now is one that worked two weeks ago a  Gigabyte GA-Z68AP-D3. I only have one computer so I will have to try to SWITCH out old one later. As I said In my last post I did the memory thing, even had a friend ( that's been building computers since he was 14 now is 30, and has built two computers for me with no problems)help me redo the computer from scratch, checked, for bad connections even cleared c mos. he thinks is a short in my case or the  powers supply. But did not have time to check either.I moved this...
Stop posting in the FAQ section...
Not the 1st time.My money is on the power supply, maybe you got it overloaded or something.  There is also room for stupid check issues.  Have you verified your system is securely plugged into the wall/power strip?  Also is the power cable securely plugged into your computer.  (I've had a situation similar to this where all my moving the cast around knocked the cable lose, ever so slightly, enough to cause power problems.)

You rebuilt your computer from scratch?  Did you apply a new tube of thermal paste on your heatsink/fan?

-Malthanks for the reply for some reason, I have to stop posting hear, Than where do I post IT!. We put thermal paste  on cpu, Like I said we checked wires . I will check power Supply today.It's in the Hardware section as it is a hardware issue.

You originally posted it in the FAQ section which is for FAQ's.Not the power supply, put new one in today, no luck. case short? do you have to have special motherboard screws. I have the brass stops in secure but two screws look a little different but screw in the brass stop things fine. What I am saying is could the wrong screws short the mobo from the top of the motherboard.  Those little brass screws are called risers and are absolutely necessary.  If you have 2 screws that look different, check the underside of the mobo, by taking off the side cover and looking for areas where the screws from the mobo are touching the case.    This side cover is the OTHER one, the one that doesn't provide access to anything.

Really the only WAY to have a case short is by having some part of the motherboard (Or screws in the motherboard) touching the case directly.

-MalVideo about testing motherboard out of case.
https://www.youtube.com/watch?v=4PXBe9FE0f0
Published on FEB 16, 2013
Quote

..just testing my new motherboard before i install it in the case.