Problem with HD 7870 Gigabyte show black screen

Is your computer turning on perfectly? If you have those beepers on your motherboard, does it beep anything other than the usual single short beep?

I have a feeling it's got to be a problem with your monitor, have you tried connecting to any other monitor? I have a Samsung s23950d and my DVI connection has a problem with it.

Hope it helps!  

My computer is working perctly. When I connect the monitor cable on my graphic card it just beep once and I can hear the windows start.
I'll searh another monitor to test.

Thanks anyway.

Did you happen to do a fresh OS install recently?

I know of at least 3 people, myself included, who have had problems with their monitors after doing a fresh OS install with a chip that has integrated graphics and a discrete video card plugged in at the time of the install.

For me, Windows failed to install any support for the iGPU due to my HD 7870 being present. Indeed, the voltage settings for the iGPU didn't even show up in the bios.

I was experiencing black screens on startup, prior to getting to the logon screen.

I ended up disconnecting the HD 7870 and doing a full reinstall of the OS with only one monitor plugged into the iGPU and then only after the install was complete did I plug the HD 7870 and second monitor back in, and install drivers.

My brother had nearly identical issues with his HD 6850. My other computer had no problems at all in the same situation with an Nvideo GTX 560 Ti. My admittedly small sample size indicates Windows fails to adequately recognize AMD video cards when there's an onboard Intel integrated video chip.

A good test for it is to put a Windows install disk in and see if you can boot up to the install screen. If so, try doing an in-place upgrade install (which should leave everything alone), or worst case do a refresh and have to reinstall a bunch of stuff.