A diag utility that runs from CD or USB would be my preference.
I'm having some trouble with a desktop PC that I support, and I haven't been able to figure out what is going on with it. I used Memtest86 to rule out the RAM, but I'm wondering if the motherboard or CPU is the issue. In the BIOS, I'm told that the vcore voltage is not right… I replaced the power supply, but that did not help. The computer will randomly freeze up.
Ultimate boot cd would be the first thing I would use.
You could try this. It is a Linux Live CD. Stress your CPU and hard drive. If the system carries the load, then you might have issues between your motherboard and RAM. I had random freezes in the past, the memtest shows nothing, the system carries the CPU and HDD load, but still freezes on random intervals in Ubuntu. No traces in the logs. It turns out the motherboard was defective, which they did not find on the first time.
The vCore voltage is the voltage supplied to the CPU, any issues/variations in this would certainly cause the OS to freeze. If you have replaced the PSU and haven't enabled any clocking/turbo/go-faster-stripe options in the BIOS then you have a faulty cpu/socket/mb.
You could try the hardware vendors website to see if they provide any diagnostic tools that you could run against the machine.
