PLEASE HELP- Random, complete shutdowns on two different machines

[StartedTheFire]

I have a baffling and frustrating problem running Linux on two entirely different machines. I have spent many, many hours searching for the answer and I have found absolutely no one with the same problem.

Starting a few months ago my desktop computer (under Ubuntu) would randomly and inexplicably shut down, without warning or any error messages. It acts as if the power has been disconnected. It is not an overheating problem as the temps now stay below 50 C after I replaced the graphics card (which was overheating.) This problem does NOT occur under windows. Recently it's been happening pretty rarely so it's been manageable.

Yesterday I got a new laptop, an Asus N53. I installed Ubuntu on it and the same EXACT thing started happening. I didn't believe it at first, thought I must have accidentally unplugged it or something. But no, the same problem was happening. So I assumed it must be the install disk as this was all they had in common, and I installed Debian. It installed fine but eventually the SAME PROBLEM BEGAN TO OCCUR.

Two different machines. Two different linux distributions. The same untraceable, unrepeatable problem which no one else in the world seems to have.

The only thing they still have in common is the internet connection (it's not the power since it happens on my laptop while running from the battery.) Does it even make SENSE that a faulty internet connection could do this?

I need to be able to run linux. I can not stand windows. Everyone says "just be a normal person and use windows" but I just can't bear it.

Please help. I'm about ready to smash things here.

[hans51]

While there may be thousands other reasons
your profile unfortunately says nothing about you or your location

I have the same - if I run without additional protection

what you encounter would/could be a sure sign of OVERHEATING
I live in a tropical paradise (Philippines islands and sometimes in Cambodia(
both my work locations by default exceed allowed maximum operating temperature for all electronic consumer goods
normally default max environment temperature is 35 degrees Centigrade

if you run any computer/laptop in such a high temp environment with or without fan ON
most likely after any time of several minutes the computer (more precisely the CPU) does an instant security shut down without warning, without actually shutting down and often with some repairable file-system damage or even data loss

what I do to prevent such instant shutdowns are multiple steps at once
1
I chose high end laptop with high quality fan
2.
I run my laptop at a location with free space all around for free air circulation
3.
I make sure my laptop NEVER ever is on a soft surface such as table cloths or bed but on a flat hard surface to assure the FULL limited space UNDER my laptop is FREE for ventilation
4.
I daily clean ventilation ENTRY UNDER my laptop
5,
I run my laptop in air con environment and keep the room temp to some 27 degrees C that has proven safe and free from any instant shutdown
6.
if no air con available then I have an external fan blowing directly from behind my laptop into the FREE space under may laptop to provide additional cooling
with that external STRONG table fan method I manage to stay save even in temperature around 36 degrees C provided I have open windows to allow fresh air ventilation through my room
that latter method I successfully use for long working periods in Back home in my little house in a hot tropical environment

without such a.m. overheating protection - I have same shutdowns or actual instant crashes as you have.
of course you could have same overheating problems also in colder zones in hot rooms with limited or no ventilation around your computer

[StartedTheFire]

That may be it. I'm in chicago and it's summer so it's pretty hot. It's just strange because the desktop had a lm-sensors frontend running and never got over 45 C for the CPU's. However, one of the thermometers was broken....

Now I've installed ubuntu 10.04 on my laptop and it works fine. It does seem considerably cooler than it was before.

[StartedTheFire]

Also, those are some pretty sweet living arrangements!

[masinick]

I'd have to agree; the only time I have seen bizarre shutdowns for no reason has turned out to be one of two things: either the power (on a laptop), thought to be plugged in, got loose on one end or the other and battery reserve got to a critical level. That one is pretty easy to spot though. The other one, also most common with laptop units, is overheating. The reasons vary - bad fan, poor circulation, high temperatures in the area, etc. The solution is to keep the circulation and the temperature down. On a couple of Dell Latitude models in the D600 series, these tended to run hot. Getting one of those lap holders with a fan source that you can enable by plugging the lap holder into a USB port nearly always solves that problem, and it can be used as needed.

I guess those holders are called "Laptop cooling pads" - some examples of them are at this site on Amazon.com in case you want to take a look and get an idea: Amazon.com: Laptop & Netbook Computer Cooling Pads

[hans51]

Also, those are some pretty sweet living arrangements!

these "pretty living/working arrangements" are the result of some 4 decades of professional preparation/work/learning
and the modern mobile computing with broadband 3G on laptops and proper job selection.

Hence something all can do if you want to serve the world from your own dream location