'No Signal' When Monitor is connected to GPU

[Sanjid]

I installed a new Graphics card today (Asus Strix 1070 O8G) but when I connected my monitor it's not getting any signal from the GPU and the monitor switched off.

System specifications -

OS: Windows 10 64bit
CPU: i7 6700k
GPU: Asus Strix 1070 O8G
PSU: Corsair RM850x
RAM: 32GB

note:
I also tried to connect my monitor to the on board video port when the graphics card is on the board as well(I know this is absurd) and Monitor still not getting signal from the board not even from the graphics card. I removed the graphics card and connect the monitor to onboard port & and it's working fine. It's just not showing anything when I install the GPU or connect it to the gpu's DP, HDMI port. I am noob so don't know what to do in this case.

Suggestions would be appreciated.

 

[Paul NZ]

If the GPU needs power did you connect power to it?

 

[Sanjid]

If the GPU needs power did you connect power to it?

of course I did

 

[BringerOfTea]

did you by any chance use the onboard graphics before installing the gpu?

 

[Paul NZ]

If the GPU needs power did you connect power to it?

of course I did

You'll be surprised that a lot of people dont know that you have to

 

[Sanjid]

did you by any chance use the onboard graphics before installing the gpu?

yes.. the board has onboard graphics.
and never used graphics card before.. this is the first time I am using a graphics card.

 

[BringerOfTea]

okay... can you connect to the onboard graphics? and then see if you get to boot?

 

[Sanjid]

okay... can you connect to the onboard graphics? and then see if you get to boot?

yes.. I tried. I tried to connect the cable from GPU port to the onboard graphics/video port as well but still not getting any signal on my monitor. Then I removed the Graphics card & turn on the computer & monitor getting signal from the onboard grpahics/video port.
Seem like my computer is turning On when I install the GPU but not showing anything on the Monitor. So to get the signal on Monitor I had to remove the card.