"New" PC build powering then instantly cutting out, even though it was working before?

[Tom_129]

Basically, I'm building a PC and it was going fine with no issues and I waa able to get into the BIOS.
However, I needed to get a different boot drive and so I shut it down.

Now it literally just doesnt work of the 4 pin CPU wire is connected to the motherboard, it just starts the fans spinning and mb lights then cuts off again.

I've tried isolating the issue but nothing makes logical sense - a different PSU (although notably much lower power rating on the second psu) had the same problem, the issue being MB or CPU makes no sense as it was working before, GPU is fine as it sometimes even outputs the bios intro to the screen.

Any ideas?

 

[Tom_129]

Bump?

 

[cherry blossoms]

Posting your hardware specs would probably be a reasonable first step so that people can offer appropriate information.

 

[Tom_129]

The specs are as follows:
intel core 2 extreme q6850
GTX 660ti
ASUS P5QL-CM Motherboard
LMS X700 PSU

The thing is, I got it to work again by bread-boarding and resetting the CMOS, however, when I again shut it down and places in the case it wont retain power. Aa far as everything os concerned there is no hardware issue as it can even display to the screen for half a second before shutting down.
I really have no idea why it isnt working, it doesnt make any sense.

 

[cherry blossoms]

How old is the CMOS battery and does it need replaced?

Hmmm..can you RELIABLY run the system in breadboard mode? Can you REPEATEDLY and RELIABLY access the BIOS from both warm and cold boot states over and over and over and over?

 

[Tom_129]

Okay, thank you everybody but I figured it out myself. Basically the case switch was faulty and so it was powering off. When the pins were shorted using a screwdriver outside of the case it would boot fine and not cut off at all. Now the system is working perfectly well running Ubuntu, just gotta figure out how to get windows on it now.