From: Uphill41 on

Had a "multicoloured vertical lines on screen" problem with an Acer
Aspire 7520G laptop and found a solution, which may be handy for others.
Feel also free to comment if you have explanations for some of the
rather strange observations made before finding the final solution.

For reading the solution only, just skip the comprehensive text
explaining the symptoms observed and the consideration and
troubleshooting done, and go directly to the end of this text. You may
find some clues in the text here, though.

Symptom: Multicoloured vertical lines started appearing and made the
computer stall, and the fan-area was extremely hot. Probably
over-heating I thought ! After cooling down 10min the laptop could boot
again, but stalled again after some time - again with multicoloured
vertical lines and a very hot fan area. After a few days the computer
could not boot at all - only vertical lines appeared, which actually
developed over a few minutes to a totally white/grey screen. Very
strange !

Troubleshooting 1: After de-mounting the fan I found a thick dust mat
partially blocking the hot air flow out of the fan. This was what caused
the overheating problem, so I hoped this could solve the whole issue.
But wrong ... still when booting, the monitor was only multicoloured
vertical lines.

Fear: New LCD or new graphics card or new laptop ?

Hope: However - with an external monitor the laptop could boot though,
but only in "safe mode". I found out that the primary graphics card is
not used in safe mode - instead an on-board "vga-safe" card is used. For
some reason this "vga-safe" card cannot be used on the build-in LCD in
the laptop, so the external monitor was needed here.

Troubleshooting 2: Graphic Card problem or LCD problem ?
In safe mode I deactivated the graphics card in "device manager"
- Doing this, the laptop could boot normally in Vista with the external
monitor. Here the "vga-safe" card was used again (automatically).
- Without the external monitor the laptop could boot "normally" also,
but still only with multicoloured vertical lines on the internal LCD
screen. The "normal" boot was observed by hearing the Vista startup
tune.

Problem Identification: So - this was most likely a graphics card
problem.

Solution: I had heard somewhere that a similar problem was solved by
"heating the chip". Unfortunately without any procedure details (hair
dryer, lamp, oven, or .. ? ). But since I was almost sure that I had a
graphics card problem, I would like to give this approach a shot, before
buying a new card. So... how to heat: I figured that booting withoutout
cooling the graphics card would definitely heat it up. So this is what I
did and it worked:
- I demounted the cooling devide from the graphics card
- then tried to boot ... but the computer shut down after a few seconds
(probably a chip overheating sucurity ?) The graphics chip really got
hot !
- I did this boot 2-3 times, always with the shut-down as result.
- on 4th attempt something different happened ... it did shut down
again, but this time the "Acer" sign appeared on the screen !.
Connection made !
- Then I re-installed the cooling devide on the graphics chip and
booted ... voila ... laptop booted normally, and has done since.

Comments:
- don't use this procedure if you are not willing to risk destroying
your graphics card completely, since I guess this could happen when
demounting the cooling device. But if you have identified the graphics
card as the bad component, there is not much to waste.
- Since the dust mat in the fan outlet caused the problem, I have now a
routine to clean this ever 3 months or so. Doing this, I hope a similar
problem will never occur again