I know I've replied to another of your posts but the details of this one look a bit different so here goes. I've found such 'out of the blue' issues in the past to have been caused by a tired PSU (even though it worked with other boards it was just out of limits for the one I wanted it to work with). Swapping the PSU with another for testing purposes got everything up and running again. As you have 2 identical systems, just for testing purposes, can you try swapping PSUs and see if the PSU out of the other PC breaths life into the faulty one. If you have tried BIOS flashing in this state however, be aware that the BIOS MAY have become corrupted (if any flashing actually took place) so you may need to restore the BIOS using the procedure outlined on the download page readme file.
Let us know how that goes.
These 2 computers are related to a show we are running. One computer is the master computer that runs the entire show, and the other computer is a duplicate backup system that will take over in the event the master computer has issues. I have swapped power supplies from master and backup. I have also brought in my own known good power supply to test with. The power supply was one of my first theories as i tested the power supplies themselves, one showed and over voltage rating on the +5VSB which is not used in our system, but the other one is fine. The 400W power supplies are about 3 years old, and the orginal specs put the power draw around 250W, But being these computers stay on 24/7, i suspected the power supply only puts out about 300W due to heavy use and aging.
We did purchase some replacement power supplies for spare, but the +5V and +5VSB show an over voltage rating on my tester. We are talking with the manufacturer now about them, but have not yet installed them.
I am currently in also trying to talking to the video card manufacturer, but i have a feeling they will be blaming it on another company like the intel motherboard.
We did flash the BIOS, but this was after the issue started. I flashed the BIOS to a previous version and since the issue still occured, i flashed it back to the current version. No issues occured during the BIOS flashing, because it was done with the DVI monitor unplugged.
So if you've already played musical chairs with swapping parts around between the two identical systems to try and weed out the faulty bit with no success, this makes things much harder. You mentioned one computer 'takes over' in the event of the other one failing - how are they connected together and have you tried them with no connection between them (i.e. standalone)? Sometimes monitors don't like displaying the initial POST section before Windows starts to load but this is usually due to graphics card bios/firmware issues and if left long enough, windows will still load up normally and things will work fine while in Windows.
I guess another possible line of enquiry may be to look at what had changed since it was working fine the previous time the setup was rebooted (1 June?) and the time it started playing up on 1 July.
Both computers run our show control application called medialon. The program monitors both computers and when it sees that one system hangs or becomes unresponsive, it pops up a dialong window on our client computer (different system) that ask if we want to switch to the backup. They are connected by RJ45 on our network.
I have tested the system in alot of various ways. no network, no optical drive, no mouse, no keyboard, no VGA, 1 stick of Ram and then just the other, no hard drive, pulled all PCI card expect the video card on the PCIe, I have tried switching power supplies from back and master, i brought in a known good atx power supply, i have swapped video cards with the backup and spare into the master. I cleared the CMOS, switched BIOS from current to previous and then back again after no success.
The previous change to the system was on Feburary 14, 2011, when the video cards were installed. replacing the bad ones, that died (master) and were about to die (backup).
I can't get a post beep code since the Intell DP35DP motherboard doesn't have the pins to install the case speaker on the header block.
Just talking with a co-worker, we had our LCS Audio/weather computer fry it's power supply on that same day. it didn't take out the master and backup medialon computers until the systems were restarted. But this wouldn't affect the spare hardware that we have just in case.
Although i don't think it will help, I downloaded the latest video drivers from Nvidia website. i talked with MSI and they do not have VBOIS that can be downloaded and flashed onto the video card. They will however RMA the videocards one at a time.