[Ham-Computers] Computer shutting itself down

[Dave Corio]

    Wow! Thanks for all the fast responses! Let me expand on the 
situation a bit more.

    This PC has been a lemon since day one. So far, the hard drive has 
been replaced three times, the motherboard has been replaced twice, the 
CPU fan once, and the power supply once. Also, when the motherboard was 
replaced, they used a 3.4 Ghz P-IV instead of the 2.6 Ghz that it 
originally came with. All under warranty, thank goodness! It was shipped 
with a 250-watt power supply, but I have added the following:

    NVIDIA TI-4200 video card with 128M of RAM (with a big honking fan!)
    Soundblaster 24-bit sound card (also still using the on-board sound 
card)
    4-port RS-232  card
    two to three USB devices
    Added 512M of RAM for a full 1G

    All this requires power - and I suspect that the power supply just 
isn't up to all I am demanding of it.

    I have tested the memory using a stress tester, in addition to 
running the memory test at each startup. The CPU fan is clean and 
unobstructed and working very well (it was just replaced by Gateway to 
"fix" this shutdown problem). All vents in the PC have been cleaned, and 
you could eat off the interior of the PC! I also did a Windows Repair 
per Gateway's instructions in case it was an OS problem. (The OS is 
Windows 2000 Pro, if I failed to mention that)

    If I don't ask much of the CPU, it will run forever without a 
problem. However, if I put a demand on it, chances are it will shut 
itself off. I run a program called "SETI at home" which does computations 
when the computer is idle. Whenever I tell the program to use both of 
the dual processors available in the P-IV, the PC will turn itself off.

    The machine never shuts itself off when I'm actually using it. It 
waits until it is idle, then simply dies. No warning, no error message, 
it simply turns itself off. There are no events logged at this shutdown, 
although using the event viewer I can see the startup routines when I 
restart it.

    The killer part of this is that while the CPU fan runs very well, 
it's dumping the heat it vents directly into the power supply! There is 
a great deal of heat coming out the back of the PC via the fan in the 
power supply. If I hold my hand over the outlet of the CPU fan, I can 
tell it is moving the heat very efficiently.

    I am thinking of just ordering a 450-watt power supply, but with 
money a little tight right now, I want to be as certain as possible that 
this will fix the problem. Replacing the computer is out of the question 
at this time, and I also don't have another I can use.

    Sorry for being so long-winded, and thanks again - and in advance! - 
for any and all help!

73
Dave
KB3MOW