Power button doesnt shut down

I agree with Lam. I suggest the simplest and cheapest solution first.
Get a can of compressed air and blow out the heat sink completly.

Re : When i press the power button, the lights all light up, the cd rom drive spins for a second and that's it. No fan, No Post, Blank Screen. After a few seconds, it shuts off and then turns back on.

That is generic hardware fault, any faulty device can cause the problem.

The motherboard must be started with a minimal set of devices to troubleshoot.

Start motherboard with only CPU, power adapter connected (faulty battery can cause the problem), heathsink, display and one memory stick. Keep unplugged HD, optical units, keyboard, minipci cards etc.

If problem persists, eventually test the motherboard using a post card(PCI & ISA PC Diagnostic POST CARD MOTHERBOARD TEST CARD) to ensure that new motherboard is not faulty, and then if cpu has not been replaced with the motherboard, replace CPU.

Sounds like a severe hardware problem concerning your laptop's hard drive. I suggest you contact Gateway customer service to check on your warranty - your laptop is, simply put, broken. The best approach to repairing it is not to fix it yourself in this case.

Look at the area where you plug the AC adapter in on the side of the computer. HP puts a little lite there or it lites up around the area where that plugs in when power is present. If there is no lite indicating power then you AC adapter is not working and that coupled with the battery being dead is causing your problem. Your other options are to remove the Hard Drive, Ram and CDROM units and see if you get power back. If you do then you know your problem is a short in one of those. The computer should start to bios with those items removed. If it does then replace one piece at a time until it stops responding and you have identified the problem. The other problems that could cause this dead PC symptom are a blown power circuit, requires a new motherboard, a burned CPU, requires replacement of CPU which is normally a new Motherboard in an HP because it is soldered directly to the board. Check the power supply AC Adapter first as this is the most common problem.

unplug the ac adapter from the laptop and remove the battery
press the power button for about 5-10 secs

while the battery is out, plug in the ac and turn on the computer if still doesnt turn on

use a known good adapter and plug it in if it still doesnt work then motherboard needs to be replaced

hope this help

Hi, most motherboards that I have fixed etc... have used the 3.0V CR1620 Button Cell Battery which is easily available and cheap!

blow out dirts on bord, then you pack the board to avoid any bridging with the cassing

Hi there.
If its the CPU (processor fan) thats not working, it could well be the machine overheating and shutting down to prevent further damage to the machine, try another fan, if it spins up the CPU fan has gone and will need to be replaced.
If you have a working fan but it doesn't work on the motherboard, check the power supply unit as that could be faulty.

Good luck and thanks for using FixYa!!

Hi.
Continues short beeps... means a short OR no power OR loose card OR system board.
Test it without the keyboard and mouse too. Just the Processor with heatsink, motherboard, memory and Video card.
Now add the keyboard, no mouse yet.
Check also the voltage of the CMOS Battery it should be 3V.

keep me posted for the result... count also the beeps.