Firstly hello and welcome to the Gigabyte official forum. Although official it is kept going by other Gigabyte customers who hope to be able to help one another with any problems they might come across. With a view to this outcome often a little more information is required than is imediately given. The fact that you have already determined the non faulty components is irrelevant because you wouldn't be asking for help if you were so good at faultfinding, so please let somebody else that is trying to help you ask a few questions to aid in their effort to locate the problem.
Personally I would think that it could be a power supply issue, but without more information this is only a guess as I have not been given much in the way of specs which is the first question most of us would ask in this situation. Please don't go around alienating people that have only your best interests at heart!
I didnt come here to sling mud and certainly not have any problems with other members, sorry you read through this ire.
Personally I would like to delete this thread and start over with clean one.
specs
all new components
system was built in October 2013
symptoms began in late January 2014
intel i5 3470
8Gb DDR3 (2x4Gb) 1600 GSkill
Gigabyte B75M-D3H board
1tb Caviar Black WD 2nd or 3rd gen black.
EVGA 550w power supply
Asus DVDr
CoolerMaster N200 Mini Tower
Windows 7 64
This is a build for a photographer that needs to quickly convert RAW images to Tiff.
No GPU as she does not game or video edit, which is one of the main reasons for choosing this board as it enables the intel on cpu video.
Nothing overclocked: 100% vanilla speeds, no XMP profile used. (stock cooler on the cpu.)
The Fault is difficult for me to replicate, as it happens after the pc has been powered down for several hours, and doesnt show after cycling the power manually (after reconfiguring the bios). So it happens when Im not there to immediately diagnose, when she needs to get her work done.. so I get the lovely panic calls, and have to go to her house to redo the bios settings.
Win 7 was installed with AHCI compatibility, the fault sets the board back to IDE mode which was how this was discovered ~ Windows freezes at the splash screen. And of course I changed the win7 registry to IDE mode but that didnt solve the issue, nor did it solve the board reseting of course, set it back to AHCI once it was clear that wasnt the issue.
Did the standard run around, cleared the cmos with a jumper and held the power button in for 1 minute. Pulled each cable off the board, checked the connections, checked both sticks of ram, one at a time in the board.
made sure the wires on the 20+4 pin power connector were all properly connected and not getting pushed out. Power supply has the 8 Pin cpu connector that pairs with the board nicely, again all properly seated, nothing indicating a power fault; nothing scorched or indication of arc.
Changed the cmos battery, checked the front panel connection pins on the board, checked the usb slots for debris. I considered using my killawatt on the electrical outlet shes using to check for voltage drops, but I realized the cmos battery should have the bios settings covered in that scenario.
updated the bios, all the drivers to latest editions. She has malwarebytes full version running on a regular schedule, I ran several more thorough malware /virus scans. nothing turned up.
stumped, turned to this forum in hopes of similar situation reported / solved.
this is a lower end board, and not really worth this much headache imo, but if I can save her from the down time to RMA of (x)weeks, and the headache of having to give her a loaner build during that time... thats where I'm at.