On Tue, 8 Mar 2016 23:12:43 -0800 (PST),
janetn...@gmail.com
wrote:
> My Toshiba laptop Statellite C855-S5356,
Hmmm... about 4 years old:
<
https://www.google.com/search?q=laptop+toshiba+satellite+c855-s5356&tbm=isch>
> When switched on boots up to the bios stage then the screen will
> change to some multi-checker boxes (as if using a scratched DVD
> in a DVD player)
That's a failure to initialize video RAM which is shared with the main
memory. The light show on the screen and the boot failures indicate
some kind of RAM failure. As "Ken" suggested, try removing the RAM,
cleaning out any dust and debris, and CAREFULLY reinserting it. If
that doesn't fix it, try one DDR3 RAM stick at a time. If one is bad,
it will be obvious. If you have new RAM
Go thee unto:
<
http://www.memtest.org> or <
http://www.memtest86.com>
and burn a CD or flash drive with their memory testing programs. If
you're lucky, it will boot and you can test your CPU, RAM, buses, etc.
If that doesn't work, leave the RAM in place, but unplug literally
everything that can be removed. Remove the CD/DVD drive, wi-fi card,
hard disk, and any USB dongles. One of them might be hanging the bus.
There's also a small chance that the battery might be causing a
problem. Try removing the battery and running it totally on the
charger.
On the other foot, it might be a bad GPU BGA chip to motherboard
soldering job, which will take a major effort to reflow.
<
https://www.youtube.com/watch?v=cP2QOXNMA9g>
Use an aluminum foil heat shield to avoid frying the PCB.
--
Jeff Liebermann
je...@cruzio.com
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS
831-336-2558