I have a problem with my 7870 gh edition. when I play games in the monitor appears a no signal icon for 1 or 2 se

[im not a kid]

I have connect the pc to the monitor via a hdmi cable (sorry for my english).

 

[A Walker]

Are you using a pc monitor, or maybe like myself I use a TV monitor which only supports 1280 x 768 or 1360 x 768 resolution, so I usually need to change the games default resolution in it's config file, also my monitor only supports a refresh rate of 60 hertz. Both these problems give me a no signal message and a blank screen although I can hear the game starting up in the background.
So try checking the resoltion and refresh rate are correct for the monitor your using.