Maths_ :
I have, the hdmi cable works fine in my ps4 but not the pc.
Should I wait for the graphics card To come?
ok, so you have plugged in the ps4 to the same display you are trying to use with the computer?
There are many reasons and ways someone could potentially cause their hdmi to not work properly, sadly, going through everything with little knowledge can be difficult. So, if the hdmi cable, and the display itself have been verified to work, the issue could be a few things. try plugging in the VGA cable and the HDMI to the display at the same time (both on the video card, not the motherboard). use the vga output to see if the pc is recognizing and sending a signal out of the HDMI. Also, some motherboards will completely disable the on board video when a graphics card is installed. play around, it cant hurt I guess. lastly, have you made any changes recently to the hardware or software that you can think of? driver updates, new video card?
There is no harm in troubleshooting while you wait for the replacement to come. its a learning experience either way.