Entée problem with HDMI

It is a beautiful display of a fantastic size, quality and excellent image precision.
I however had a serious functional problem with the HDMI input. Let me explain.
HDMI branch to the graphics card and the screen all goes well until the first reboot after loading the drivers.
At reboot black screen and impossible to access the bios.
I change my motherboard and processor, I reintalle Windows7 and after installation of graphics drivers, always-connected Digital HDMI
the first reboot clears my bios of the new motherboard.
This is where I begin to understand that the screen is in question and in particular the digital connection.
I buy another motherboard and I connect the VGA screen and Windows 7 installation and all drivers OK,
and now my PC is OK for 6 days in the analog configuration.
I conclude, therefore, has a defect in the digital management of the screen.

If someone other than me detected the same problem, it passes in VGA or it returns the screen without having to kill 2 motherboards.
My comment was only intended to inform the cause of the PB.
I think keeping the analog VGA display.
This is not luck.