Computer starts for a fraction of a second then turns off

[TheWillP]

Hello, I have just transplanted my old system into a new case, and ever since it not wanted to start up, exept rarely where it does. When I press the power button, the fan start to spin up for about 0.25 seconds then stop. I am not an experienced builder.

 

Specs:

intel core i7 920

dell motherboard

ati radeon hd 4670

15Gb RAM

64Gb ocz petrol

500Gb wd caviar blue

generic power supply

new case: cooler master haf xb

old case: dell studio xps 435mt

[Kayn]

did your new case have motherboard stand offs? It sounds like your system is shorting out.

[darksoulinside]

if in previous case all works.... first what you should do > check all power connections

[TheWillP]

I have put the motherboard standoff screws on and I have checked my power connections, sometimes I'm luky somtimes I'm not

[Morfy]

Try ram sticks one at a time.

[Jechu182]

Thats right, check all power connections, make sure the motherboard is correctly installed to check if its not shorting out, maybe you installed a standoff wrong, check any new connections from the case like front audio, power/reset button, etc. 

[orangecat]

sounds like a dead GPU.

[TheWillP]

I have tried the ram and the gpu is not dead seeing as its turns on rarely

[TheWillP]

and I have made sure of the power connectors and the front io

[TheWillP]

but I am pretty sure about the mobo standoffs

[Jechu182]

Im pretty sure it has to be an electrical problem, like a short or something. Because that happened to me when I built my PC. I reinstalled the motherboard and the PSU and I got it working.

[TheWillP]

of I shall try that

[Chenty]

First step is to clear CMOS incase something got affected during the transplant. If still dead, then take everything out of the case again and try it outside of the case with no drives plugged in. If that fails, try removing the graphics card and running off onboard. If that still doesn't fix the problem try one RAM stick at a time in varying slots. If still no joy, try to get hold of another PSU. If still no joy then you have narrowed it down to the mobo or the processor and it may be worth just upgrading to current gen at that point.

[PartyBlake]

Make sure that you aren't shutting your case door on your graphics card's power cord and knocking it loose...I've been there -_-

[TheWillP]

Cleaning the cmos worked but i still do not have confidence about turning it on yet