POST not starting at all

[Nadril]

ASUS P5Q Pro motherboard
EVGA 9800GT
Corsair 8GB RAM (4x2GB)
Intel core2duo E8500 @3.16ghz
Roswell 600W PSU
Western Digital 1TB Hard Drive


The problem is that when we boot up the computer it will not POST. The screen is blank (on standby) and nothing shows. Do you all have any idea what could cause this? I've tried running it with only 1 stick of RAM, with and without the SATA ports, with and without any mouse/keyboard. I reset the CMOS (blue jumper pin, not the battery yet) but still haven't gotten anything so far.


What would be the cause of this? There is a green light on the mobo from the PSU, and everything turns on fine (hard drive is spinning, CD drive works, fans are going including CPU fan) but it just doesn't POST or do anything.

I've also tried switching out all of the RAM to make sure none of it is bad, and I have made sure that it is not the fault of the video card.


Also I should say that sometimes the computer will turn on for 5 seconds, turn off for a moment and then turn back on. It doesn't always happen however, and last it did was when I was running with only 1 stick of RAM at a time.

 

[marcellis22]

Get a good power supply! Don't be cheap...

 

[roadrunner197069]

8 pin CPU power plugged in?

If it is then the PSU is junk.

 

[Nadril]

From what I've seen it's a good PSU. I could be wrong about it though, but how do I know if it is the PSU or mobo that is causing the problem.

The 8 pin power is plugged in as well.

edit: for clarification THIS is the exact PSU I am using.

 

[Robert17]

Double check the cable usage from the PS to your components. If you have a low power PS, you can't hook all your dongles up to as few splits as you'd prefer. PS is critical.

 

[shortstuff_mt]

This checklist was created to help diagnose problems like this:

http://www.tomshardware.com/forum/261145-31-build-post-checklist

You have gone through a few steps in the checklist already, but I would go through the whole checklist.

 

[jsc]

After the checklist, try this:

Pull everything except the CPU and HSF. Boot. You should hear a series of long single beeps indicating memory problems. Silence here indicates, in probable
order, a bad PSU, motherboard, or CPU - or a bad installation where something is shorting and shutting down the PSU.

To eliminate the possiblility of a bad installation where something is shorting and shutting down the PSU, you will need to pull the motherboard out of the case
and reassemble the components on an insulated surface. This is called "breadboarding" - from the 1920's homebrew radio days. I always breadboard a new
or recycled build. It lets me test components before I go through the trouble of installing them in a case.
http://www.tomshardware.co.uk/forum/page-262730_13_0.html

If you get the long beeps, add a stick of RAM. Boot. The beep pattern should change to one long and two or three short beeps. Silence indicates that the RAM
is shorting out the PSU (very rare). Long single beeps indicates that the BIOS does not recognize the presence of the RAM.

If you get the one long and two or three short beeps, test the rest of the RAM.

If good, install the video card and any needed power cables and plug in the monitor. If the video card is good, the system should successfully POST (one short beep, usually) and you will see the boot screen and messages.

Note - an inadequate PSU will cause a failure here or any step later.
Note - you do not need drives or a keyboard to successfully POST (generally a single short beep).

If you successfully POST, start plugging in the rest of the components, one at a time.