Hi there,
I have this hp pavilion ze4900 laptop that won't boot up. I have tried the following but still won't boot:
1. Remove battery--remove DC plug--reset the laptop using a reset switch it has on the bottom--put battery back--plug the DC cord--turn laptop ON. At this point it turns ON, I can see the power light is ON, but no signal on the screen, no nothing.
2. Then, I reset the RAM memory module and reseated the HDD. After that I repeated step 1 above, and NOTHING=black screen, power light ON, DC light ON, HDD activity light OFF. I also realized that the CPU fan spins for a few seconds when I switch the laptop ON, then it stops.
Now I have run out of choices., since there is no way I can use the F2 key to check the BIOS settings.
Can someone, PLEASE, help me with this issue?
NOTE: The Laptop was previously working fine, it just stopped booting one day, just like that.
Thanks in advance,
osmany.

Remove the battery and the AC adaptor. Hold the power button down for 30 seconds and release it. Reinstall the battery and the AC adaptor and see if the laptop boots. If it still does nothing, the motherboard might be blown

Truly, things do appear gloomy.

Connect the VGA output to a monitor. Maybe it will give you a flicker.

As Tmagic suggested, things are pointing to the mobo. In a desktop, eliminating connecting devices is part of the troubleshooting. Opening up a laptop can complicate an already bad situation.

Double check a basic assumption that the battery is fully charged. Running on the adapter alone, the computer shut down.

BTW - excellent problem description.

Hi Tmagic650 and fr6647,
I did all you suggested and still NOTHING, but I realized that the light that shows when I plug the DC adapter is yellow because the battery is not charged, if it was charged it should be a green light, though I still think the laptop should start on the DC supply even if the battery is not charged, then keep charging the battery while the computer is running.
I will leave the laptop connected to the DC adapter for a few hours to see if the yellow light turns green.
By-the-way, will the battery get charged if the laptop is not turned ON, but just connected to the DC adapter?
I thank you both for your suggestions,
Osmany

Well I'll be

....Surprised!
The battery in my ze4900 has a built-in battery check. Current reading: 4 green + 1 yellow. Remove from laptop; narrow side, on the same side as the connector; push the finger symbol.

Specs: HSTNN-iB13 < I am guessing the 'i'>; 11.1v; 4400mAH

Adapter rated @ 18.5v, 3.5A, 65W

Voltmeter readings of the adapter can be misleading. Plugged into the outlet, but not plugged to the laptop, adapter is cool to the touch. Plugged to the laptop, warmth increases with load. I've waited 10 minutes; no change to 4 green LEDs; warmth not significant (computer not on). Laptop indicates that it is charging (yellow).

Battery charges faster when computer is powered off. A shorted battery can load the charging circuit; battery becomes burning-hot; Li-ion batteries are dangerous under these conditions. Normal dead/weak battery just work the adapter harder. The adapter is able to power the computer with the battery removed.

Based on your description, I judge your adapter to be working since the panel lights came on. Shutdown is probably coming from the cpu or mobo. But before tearing into the case, power was safe & easy to re-check.

I'm back. Laptop indicates fully charged; no changes to LEDs @ 4 green.

I've seen many laptops with this symptom osmany. You have done all we have suggested. I'm afraid that the motherboard is bad

Hi again, I tried the finger-test on the battery and it shows 1yellow+4green lights. After leaving the laptop charging for a while the yellow light for the DC supply indicator went off, even when the adapter is plugged on both the laptop and the wall-outlet.I borrowed an identical adapter from a friend and when I plug it to the laptop the yellow light does not come ON. I assume the yellow light went OFF because the battery got fully charged and, since the laptop is not operating there is no need for the battery to be recharging.
Now guys, please, don give up on me. There should be other things to try before replacing the motherboard.

Here I downloaded the service manual for that laptop:
http://www.hp.com/ctg/Manual/c00226047.pdf

Thanks once more,
Osmany

You can pick up a laptop tester for around $125. This device plugs into the wireless network slot. It displays where the startup sequence stops or even if it starts. Unfortunately, more often than not, the motherboard is the bad component. I've got an HP dv5000nr that has your symptom. The motherboard is bad. It cost $256... so prepare yourself. HP wanted $435 for the motherboard

Ok Tmagic650, thanks anyway a lot for your suggestions,
Osmany