Intermittent Reboot with no BSOD??

Yes, it will still crash.

I get the feeling that a windows service is accessing a device or memory area that then causes the reboot, it has to be a hardware fault, i just don't see it being an incompatibility error between hardware.

The only 2 pieces of hardware left is the RAM and CPU. I've tested the RAM DIMM by DIMM and it still reboots, but perhaps it isn't fully compatible with the CPU or MB, I don't know, I can't find anything to suggest this is the case.

The CPU passed all the tests, but is this conclusive??

Agreed.

I just purchased new memory that is compatible with the MB and CPU, if that doesn't fix it, it must be the CPU.

Cheers.

Update...

Installed the memory and all appeared well. The system appeared stable during the day browsing the net and running Spotify until I went to install a game.

Soon after the install started the system rebooted, I then attempted to copy a large iso file from my server and this also caused a reboot!!

I now have a new CPU arriving today, this is the last part to be swapped out, if this doesn't fix the issue then the pc must be haunted.

Update..

I don't want to tempt fate, but the new CPU appears to have solved the reboot issue!

Thanks for all the help.

T.