System crashing???

I am experiencing a problem, the cause of which is proving to be very tricky to locate. Perhaps someone out there will have experience of a similar thing or maybe some other ideas to put forward.

I have 'upgraded' three machines, two in an identical manner with the third being similar. In fact the upgrade represented a complete rebuild, retaining only the case, PSU and floppy drive. The new spec of the two is as follows...

Disk Hitachi 40Gb
Mainboard Asus A7N8X
Processor AMD Athlon XP 2500+
Graphics sparkle 32MB AGP
Memory 256Mb PC2700 DDR
OS Windows XP Pro

(the third machine is similar but with 512Mb RAM, a CR-RW and 750Mb ZIP drive and a lot of application software - but shows no problems)

Machine 'A' has been running without problem however machine 'B' has shown the trouble.

Before moving to the new system running XP, the machines were running an old DOS application for 3-4 weeks and no problems occurred however having now started using XP (which *could* just be a coincidence) very occasionally machine 'B' will either lose its signal to the monitor and refuse to start up again or will simply reboot itself. In the first case the main unit has power on although I've not been able (yet) to find out whether it is still running (via the network) and the only way to get things going again is to switch off the machine.

This problem is so occasional that the machine can run for a week or more without problem and then it can suddenly happen (when starting up from cold).

At the moment I'm trying to eliminate (or detect) faulty hardware by swapping over components and have ruled out the graphics card. I've run extensive memory tests on the RAM with no problems found and have currently swapped the memory and CPU and am waiting for a failure to appear somewhere.

Could it be a software problem?

I do recall that when I was putting the machines together I had problems installing the supplied drivers for the graphics card and it would only work on one of the machines, the other two machines would crash and so were built using the default XP drivers. Sadly the notes I made at the time detailing whihc machine was which in this case have gone missing.

One job I obviously need to pursue is to try and get some better graphics drivers and see if they help.

Any other ideas?

My experience with the Nforce2 boards is that they need a good power supply and are at times picky about ram.

You say that you tested the ram so I guess that meant things like running Memtest 86 or Prime 95 and they both ran error free ? did you try the ram in different banks ?

Floppy drives can go bad and cause a crash on bootup floppy seek, disable the floppy & test.

Cold boot problems are usally caused by the video card or a not so good motherboard bios.

If your crashing in Windows I would be looking into the software that caused the crash, the ram or the video card.

Go to >Start >My Computer >Properties >Advanced >Startup & Recovery >Settings and under System failure uncheck the box *Automatically restart*, now when you crash you should get the error message instead of a restart....that should help in finding the problem.

Go to Start > Acessories > System Info > Hardware Resources >IRQs and see if anything is sharing a IRQ.

On the A7N8X go into the bios and disable all the onboard perf's that your not using.

FastGame has covered most of the things I would try. The things I might do a little differently follow:

I personally, have had more problems with memory in cold boot situations than other hardware. Flaky video cards have run second. Until two weeks ago, I would not have even considered the CPU. In that case, I was trying to upgrade an older MB with the new Duron 1.6 MHz. With no bios upgrade available, I had to give up on that project.

In testing cold boot issues, it is easier when you narrow your focus by reducing the number of variables. When I have a suspected memory issue, I will swap memory banks for the first try (assuming two banks). If that doesn't help or if the MB has three banks of memory, I will test the memory, one stick at a time. If it works with each stick individually, yet has a problem with two or more sticks mounted , the problem is a flaky stick that refuses to work with the others. Testing two at a time will eventually reveal the problem stick. I have run into that situation more than once.

As FastGame stated the video card is a likely candidate. I keep an old Banshee 16MB card around just for that purpose. It has never failed to install and work on any MB that I have tried it on. It is a quick way for me to test the new video card. That is a good reason to keep old components. You never know when one might answer an illusive question on your latest project.

One last point: If you do frequent hardware upgrades, consider purchasing a PCI Post Diagnostics Test Card. It is a $35 investment that can save countless hours when dealing with boot issues. If you are not familiar with this item, the following is related to the StarTech.com card.

The StarTech.com PCI Post Diagnostics Card makes troubleshooting PC problems easy. Simply plug the card into a PCI slot on a malfunctioning PC, and the card reports any problems in the form of error codes on its LED display. These codes are then cross-referenced to the enclosed error code chart to pinpoint the cause of the problem. PC technicians and system builders can save hours of troubleshooting time and prevent non-defective parts from being replaced.

Many thanks for some really useful ideas!

A memory tester has run several clean passes so I tend to think that the RAM is probably OK, although I've currently got it swapped with the good machine to see where the problem next occurs. I could still try it in a different bank, however.

The video card itself has been swapped with the good machine and the bad machine still failed which suggests that the card is OK although I'm currently getting the latest XP drivers for it to see if they help.

I think maybe disabling the auto-restart could prove to be the most informative.

The biggest problem I have is that it could run quite happily for many days before it crashes again!