no screen input HELP ASAP!

[duckisflixma]

So i have a very strange and also serious problem with my pc the problem is that i don't have input signal to my computer from my gtx 780 graphics card once i plug my hdmi to my motherboard i do have input signal i also used another graphics card to my computer a gtx 570 and it worked perfectly and then i pluged my gtx 780 that is not working on my computer to another computer that is a clone to my current computer with the same specs"

After i plugged my gtx 780 to that computer it works perfectly but when i plug it to my computer it has no input signal i also changed my psu with a brand new one and still did not work i changed my cpu aswell and same results.

I also changed my memory card and my ram and after all that my pc does not work with the gtx 780 but works on my friends pc that has the same specs

So what is causing this and how do i fix it i tried everything and nothing worked please help me!

 

[duckisflixma]

And also my pc bots up fine with one beep but has no input signal with my gtx 780