unexpected reboot

[Xandros Pilosa]

NoOp pravi:
> On 09/01/2009 11:49 AM, Etienne wrote:
>> Looking for DSDT in initramfs
> 
--snip--
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/58386
> [ACPI: Looking for DSDT ... not found! (message during boot)]

I think we are barking at the wrong tree here.
See post #8 in above link.
Error message "...file /DSDT.aml not found..." is very usual nowadays. 
This simply tells us, that we did not (and usually we don't have to) 
override manufacturers firmware DSDT like described in posted link below:

--snip--
> DSDT info:
> http://www.lesswatts.org/projects/acpi/overridingDSDT.php
> 
> Because the msg is BIOS related, I'm wondering if perhaps your machine
> shut down due to the CPU fan not turning --snip--

Beside already mentioned fans and high temperature, I would think about 
power supply  misbehaving.
If it happened just one time and temp./voltage readings from motherboard 
sensors are o.k, high/low voltage momentum in the el. grid may also be 
the problem.

Regards