Some strange hardware failure

[yaro137]

Girlfriend's laptop started restarting. I ignored the problem for
far too long. Eventually it crashed and didn't want too boot again. I
opened it up, cleaned and tried to start it. Well, it started, sort
off...

I could hear the drive spinning, the CPU fan was also spinning
from time to time but nothing on the screen. OK. I thought it's either
graphics or the monitor. Just for the off chance I tried swapping the
memory and CPU. Then tested the HD on another system. All works fine.
So graphics or screen again I thought. Then I noticed that every now
and then when I was trying to start it I could see some light in the
bottom of the screen. I cleaned the graphics chip and replied the
heatsink compound. It started and the screen showed me that Windows
(Vista) has recovered from a serious error and the system is trying to
repair it. It failed, but anyway I new from that moment that the
graphics and the screen work. Just to be sure the system failed
because the laptop was all in pieces I put everything together and
tried to start it.

Disk and fan CPU fan spinning nothing on the screen. Not even
that light in the bottom. Then I remembered there is something called
inverter or something inside the screen. If that's failing I wouldn't
be able to see anything on the screen. But then why it started
perfectly normal before?... Although it would be easy to test the
screen by connecting the laptop to some external monitor I just cant
get a simple VGA cable anywhere. They're all DVI now.

Does anyone know if it was a failing inverter indeed would it be
behaving this way sometimes working other times not?
Thanks
yaro

 

[yaro137]

Looks like it's not the screen after all. I managed to get a VGA
cable, connected the laptop to my monitor and then when trying to
switch between screens I noticed that the keyboard isn't responding.
The touch pad has a button that disables it. When presses this turns
red. It doesn't work either.

I'm running out of ideas. Would it be the motherboard that's failing?
Any way to test it without the need of replacing it? Also I'll try
getting the memory dump file from the disk if there is such and see
whether this gives me any clues.
yaro

 

[yaro137]

Fixed...

Well, sort off. At least it can be used again.
Turned up that one of the memory slots is damaged.
When I left only one memory chip in the system started so I added the
second
memory chip and had the same symptoms as before. Then I removed the
chip
that I knew is good as the system successfully started on it and put
the one I
thought for a moment that somehow failed although I tested both of
them on
another laptop a couple of days before. Amazingly it started just fin
again.
Then I thought lets try putting it into the other memory slot...
That's when
it failed. The other memory chip didn't work in that memory slot
either.
Apparently there is something wrong with the motherboard after all.
Now I just need to put larger memory chip in the good slot for Vista
to run properly as with only 512 RAM it's just too annoying.
Thanks.
yaro