It was just this morning when I tried to turn my pc on.. unfortunately it did not. ! when i press the power button on cpu it turns on for a few second like one or two but immediately after it drops the power supply. CPU fan also starts and stops. however the small light bulb on motherboard is on. but no start up.. i also removed RAM and re-planted it.! Nothing happens..! Can Someone direct me as to what is wrong with my pc. ?

Have you tried pressing space bar (maybe its in hibernation mode) ?

or try holding power button for a few seconds (10) then turn it back on.

as a last resort you could try take the battery out, disconnect it from the power adapter, hold down the power button for 30 seconds and then place the battery back in and the power adapter and try powering it on?

Hi John,

I'm sorry to say, I believe that you have a bad CPU. Laptops, unfortunately, don't breathe very well. This means heat is a problem. Heat kills CPU's. The fact that your power and bios seems to be functioning correctly (power problems don't allow lights to come on etc... typically and when you pressed the power button and drained the CMOS battery, the board did what it was supposed to do and reset itself and, in lighting up as usual for the first few seconds, starting its POST again, you can gather that it is functioning correctly). Of course, I'm some guy on the internet, so I'd recommend that you have someone qualified do a proper diagnosis. I apologize for your unfortunate experience. The good news...... the CPU is replaceable and that particular CPU isn't that expensive. Let me know if/when you confirm this and I will help you with replacing it.

Regards,

Kevin

Hello Alienware,

Could be a few things.... such as the micro-fuses that have gone on the MB....

But what I dont understand is this:...."Then I disconnect the 4-pin cable that goes from the Power Supply to the motherboard near the CPU and the pc turns on fine"

How????
You have just disconnected the cable from the PSU to the motherboard....it CANT turn on! LOL.

Do you mean that the lights turn on?
Or you hear the HD spin up (if you left it connected to the MB that is)?

Please advise so I can help you more.

You're typing like you have been working tirelessly on the problem.
In fact there is no user name, lol!

Okay.....relax...........just ease back, and put your hands behind your head, and close your eyes.............think about clouds floating across in the sky.

Better?

Alright.

Your Power Supply is bad. Weak voltage power rail.
Replace it.

Don't think so? Cool.

That's what I'm here for. To teach.
Have a multimeter?

A) If ALL of the LED's were on they would use less than 1 Watt of power.

B) EACH fan uses 2 to 3 Watts of power.

C) A typical Processor can use 51 to 125 Watts of power. Just depends on what Processor it is.

(Older Intel Pentium I, II, and III, uses less than 51 Watts. Some older AMD's do also)

Primer:
You press the Power On button. The plastic assembly of the Power On button in turn presses against a Power On switch,

http://www.directron.com/atxswitch.html

The Power On switch is a Momentary Contact Switch.
When briefly closed the Power On switch completes a circuit.
The Soft Power On circuit.

When the Power Supply is plugged into power, there is a constant 5 Volts (DC) present.
The 5 Volt Standby power.

Pressing the Power On button redirects the 5 Volt Standby power, in the Power Supply. This 'excites' the Power Supply, and turns it on.
(Soft Power On circuit)

The first chipset (I.C.) to receive power is the BIOS chipset.
The Basic Input/Output System program is initialized.

BIOS looks to see what devices are installed, does a Ram Memory count, TURNS the Processor on, and hands the computer over to the Operating System.

(WinXP and Win7 are two examples of an O/S)

Primer over.

1) http://h10025.www1.hp.com/ewfrf/wc/product?cc=us&dlc=en&lang=en&lc=en&product=405454&

2) http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00595250&tmp_task=useCategory&cc=us&dlc=en&lang=en&lc=en&product=405454

FOLLOW Anti-Static Precautions

2a) http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&taskId=125&prodSeriesId=3433073&prodTypeId=12454&objectID=c01358034

(Yes, I know. Slightly different computer case. Principles still apply)

3) Don't think you will be hearing any BIOS Beep Codes, because there isn't enough power, lol!

For additional questions please post in a Comment.
Regards,
joecoolvette

(If Power Supply power were dynamite, your Power Supply wouldn't have enough power to bl-ow it's nose)

Press Ctrl+Alt+Del "Delete keys" simultaneously.
Select "Turn off" or "Shut Down" by clicking on it. orClick on Start button>Turn Off or "Shut down" computer. else, Press the power button of your CPU for a few seconds.
Hope it will be helpful to you
All the Best!

Did you flash the main board ??

1.) remove battery
2.) press and hold the power button for 10 - 30 seconds
3.) replace battery.
4.) when the system boots it will say press XX (e.g F2) to load defaults and continue ,, press that key.

It could also be the power button is stuck!.

find were it connects to the main boad and unplug it
bridge the 2 pins it jacks into to turn the computer on. if it works u will need to replace that button or the case.

You could have an overheating problem. The CPU shutsdown when it overheats and won't boot up again until it has cooled down. Check the CPU fan and heatsink assembly. The fan may have stopped spinning or spins slowly and the heatsink is clogged with dust.
Remove the dust and replace the fan if it is faulty.

First of all when you switchon your PC, checkout whether your processor Fan is running. Because problem might be because of SMTP failure [Power Supply in your CPU] if its working fine and you are able to see LED glowing in *********** board, might be loose connection in your Hard disk cable.
Let me know this didn't help you out or if you need more info.

I have seen systems where when they get an unexpected shutdown such as a power failure, then the power supply will not supply full power when you try and start back up. I would suggest that you turn off the power switch to the power supply (if you have one), what a few seconds and power it back on.

Laptop will def not power up without ram or cpu.

Can you test the hard drive in another pc?