Computer resets by itself

I have a pretty basic home made computer. When I am in the internet (its
primary use), it has wild resets. As I am browsing, it resets by itself.
I think it happens when it refreshes a screen or open a new window... I am
starting to believe that I have a bad video card.
I have replaced a few parts to try to identify the problem, but I still
has wild resets.
The computer is:
MSI KT6V motherboard Socket A
Sempron 3300+ Socket A (I replaced from an Athlon 2100+)
MSI Nvidia AGP Video Card Gforce 2 MXMX 400 64 MB
Diablo Power Supply 550W (Replaced from a 300 W PS)
1 GIG DDR Memory (replaced from a 512 DDR)

It used to reset just as much with the old parts as well. I was going to
replace next the AGP video card.
The BIOS has an option to turn off the cpu if the processor overheats:
Disable.

Any thoughts....

Thanks,
mac

In article , "badgolferman"
wrote:

mac, 7/29/2006,8:48:25 AM, wrote:

I have a pretty basic home made computer. When I am in the internet
(its primary use), it has wild resets. As I am browsing, it resets
by itself. I think it happens when it refreshes a screen or open a
new window... I am starting to believe that I have a bad video card.
I have replaced a few parts to try to identify the problem, but I
still has wild resets.
The computer is:
MSI KT6V motherboard Socket A
Sempron 3300+ Socket A (I replaced from an Athlon 2100+)
MSI Nvidia AGP Video Card Gforce 2 MXMX 400 64 MB
Diablo Power Supply 550W (Replaced from a 300 W PS)
1 GIG DDR Memory (replaced from a 512 DDR)

It used to reset just as much with the old parts as well. I was
going to replace next the AGP video card.
The BIOS has an option to turn off the cpu if the processor overheats:
Disable.

Any thoughts....

Thanks,
mac

I would suspect the headers from the front panel switches first. Wiggle
the connectors at the motherboard and at the switches themselves tosee
if you can recreate this effect. Next I would suspect the power supply.

The first thing I would do, is disable automatic restarts. Then,
when it crashes, you should get a blue screen with numbers on it.
Maybe the code it crashes in, will have a recognizable driver name,
which may point a finger at a particular piece of hardware.

If disabling automatic restarts doesn't yield a blue screen, then
that means you are getting a hardware reset instead of a software
crash. Then I would start looking for a hardware reason.

Have you done the basics on your system ?

1) Run memtest86+ from memtest.org . Two complete passes error free
is enough testing. If there are errors, try turning up the
Vdimm if there is a setting. Otherwise, slap in the 512MB stick
and repeat the testing. Try a different DIMM socket.

2) Run Prime95 torture test (mersenne.org). This runs in Windows.
If the computer resets the very instant the test starts, then
the problem is power supply related or Vcore regulator related.
(I might try another motherboard in this case, as you are on your
second power supply.) If the program simply reports an error and
the computer continues to run, it could be CPU/memory/motherboard.
If it runs for hours, error free, then the CPU/memory/motherboard
are looking better.

3) Run 3DMark2001SE. There is a benchmark option and you can run in
"demo mode" in a continuous loop. If the benchmark crashes
instantly, it could be video. Hard to say otherwise.

None of the above tests use Internet Explorer, or the network
interface, so they will simply add to the data available to you
about the health of your system.

Paul