I tried the passmark software (5.1) on a system and it passed the tests. When I went to turn the system on again the next day, the power went through the mobo but no image was sent to the monitor. I was using a high end Asus mobo (A8N32) and a Geforce 6800 PCI-E card. I phoned Asus who went through a series of tests (new graphics card, RAM etc) and pronounced the mobo dead. I sent it back to Ebuyer who also said the mobo was dead.
They then sent me a new Asus mobo (different model though A8N premium) and I rebuilt system with this. It was up and running perfectly for 2 hours whilst software was installed, updated and tested and rebooted a few times. Then I ran the burnin test (5.1) and it passed. I shut the system down for a couple of hours then rebooted and, as before, no graphics.
Anyone ever come accross this before? Any ideas?