My brother in laws computer just start shutting down on him randomly. I took at a look at it to see if I could witness it first hand and I believe it is an overheating issue. I used everest home to see what the cpu temp was (cause his computer is too old to use core temp). It appeared that his computer would shutdown around 130 degrees.
The cpu fan is working but there is no other casefan. We tried hooking one up and blowing on the cpu as close as we could and noticed it would reduce.
We've never changed any of the components so I'm just curious what would cause it to start over heating all of a sudden. Is it possible the heatsink can come loose?
This happened to me once at work on a computer that was about 8 years old. It was a dell wit a P3 that didn't have a cpu fan. One day it started over heating so we put a box fan next to it and it was able to run fine until we finally retired it.
I'm not positive, but I would think that the heatsink's fan can wear down and not perform as well as it gets older. Also, the age of other parts can cause additional heat, mainly the PSU. Dust and other build up can also cause a reduced airflow.
The case didn't have any fans? That just seems odd, and very poorly thought out...
If you've had the machine for a while, it's possible that the thermal paste on the CPU heatsink has baked itself into a brittle mess that doesn't transfer heat very well. Quite likely, in fact. So first thing I would try is removing the old compound (with the proper cleaning solvent, of course) and reapplying a new layer, preferably Arctic Silver. It's a good idea to do that every couple of years if you can help it.
If that's not it, it's also possible, as others have said, that the CPU fan itself is just getting old, or that dust is gunking up the airflow.
I also find it pretty odd that there would be a machine with no case fan whatsoever, although without knowing the rest of your system specs, I suppose it could be possible.
My bro in law said he blew out the case pretty thoroughly with an air compressor to clean out the dust bunnies but I'll double check under the cpu fan cause I know they can sometimes get stuck in the heat sink grills.
The case did not have any fans beside the cpu fan so yeah probably not thought out too well but it held up for at least 4 years (I think its that old, probably older). I have a tube of arctic silver 5 from a recent build I did. So I'll also look into resetting the heat sink.