ProBook 4320s - dead?

So, I got my fathers laptop - 4320s.
Two days ago everything was fine, he did his stuff and set it to sleep (with AC power plugged in).
Yesterday he wasnt home, so computer wasnt touched, only mother have been cleaning around to remove dust.
Today comptuer wont turn on.

Today in the morning, before someone tried to turn it on, they had a power shortage for like 2 hours.

When laptop is plugged in to AC power, power led is flashing quite fast - turns on for a blink of an eye and repeats it every few seconds. Doesnt matter if battery is present or not - if AC power is on, led blinks.
When battery is present, after pushing power button, power led turns on for few seconds (havent counted, but 3-5 most likely). Then power led turns off and keeps blinking as before.
Fans or any other leds dont turn on, only the power led.
If battery is not present, nothing happens after pushing the power button.

AC adapter got some noise (like a bee or a fly or smth, dunno how to tell it in english) in it, but I think its not guilty, cuz it have this noise since I bought the laptop, and, besides, I have tried to turn the laptop on with my own AC adapter from 4720s laptop.
Also I think that there shouldnt be any static electricity involved, since the AC adapter was present (it should remove any impulses with the negative power line).

What I have tried already:
1. I have tried to turn the laptop on with AC adapter and battery present, without the battery or AC power, nothing happened;
2. I have removed CMOS battery and made a power shortage with a coin inside the slot where CMOS battery is installed;
3. I have tried removing RAM, HDD and like every other device that is not soldered with the motherboard, in case some charge have been hiding somewhere;
4. I have tried doing hard reset with removing AC power, battery and pushing the power button for like a minute;
5. I have tried turning it on with another AC adapter;
6. I haeev tried turning it on with pressing the power button a lot, holding it pressed for a little etc, like every possible pressing style u can imagine.

There is nothing else I can think of, I dont have multimeter with me, so I cant check if the power is going around the motherboard, and if the AC adapter have been giving out the right voltage (power led is blinking, so AC adapter aint completely dead tho).

Any ideas from some more experienced people? Have anyone saw and solved any similar problems?
I got kinda theoretical idea about something being wrong with the standby chain, because laptop was in standby, when there were the power shortage at my parent house, maybe it screwed something up with the power management settings (no standby/hibernation, when AC is plugged in, but standby/hibernation is on when running on battery and that kind of stuff).

Basically I got almost a year left of the warranty, so I'm not stressing yet, the only thing is that I'm not really interesting to go screw around with it, and I guess my dad get to live without his laptop for like a month. Also I dont rly want to take the laptop apart again and copy dad's information from the HDD, because, after the warranty services, it will most likely be gone.

So, any ideas? I would rly appreaciate any kind of help with your experience or ideas.

 

Seems like your dad leave the pc plugged in so much, which WILL! cause it to go bad. Try changing the AC adapter, you will see!
-the symptom of turning on 4 a few seconds seems like the battery has some charge
-since ac adapter is dead u u cannot turn on, since it has no power, without the batter
JUST TRY CHANGING THE AC APADTER AND REPLY!
GOOD LUCK!

 

As I said before, I tried with my AC adapter from my 4720s (its the same as 4320s, only mine is 90W instead of 60W) without any luck.
Besides, AC power led blinks with the old adapter either.

 

does the light on the power adaptor go off when you try to switch the computer on/plug it into the machine?

one other thing to try is press and hold F2 before switching it on.

it sounds like a short to me, or the bios is in a state which it's not happy with.

 

Its most likely a short according to you, because nothing happens if I press F2 and I just noticed that an AC adapter is making weird noise when plugged into that laptop. Mine AC adapter is making the same noise when into that laptop, when its plugged into mine, there are no noise at all.

 

ah sounds like a rectifier has gone.

in english, the motherboards power regulator which splits the power coming into the machine into different areas, is controlled by 4-5 3 pin chips which sadly can fail over time.

just get it warrantied in, - and don't plug your PSU into it anymore, or you'll be needing a new one of those as well

sorry to be the bearer of bad news :/

 

Its cool, we got kinda nice warranty service, maybe, after I send my laptop to them I'll get brand new one ina a box with an extra AC adapter and an extra battery.