PC wont detect GTX 970

[theory.julian]

My GTX 970 wont work with my PC. I have already tried using a DVI cable, same thing happens. Whenever I plug in the HDMI cable into the 970 and boot up the PC, nothing will show up, the HDMI cable only works with the HDMI port that is directly connected to the motherboard.

 

[hang-the-9]

Need more details, did this work before? Does the card work in another system or another card in yours? Need full system specs including power supply brand and model. Did you just buy the card and was it used? If it was used, did you test it first to make sure it worked fine? All needed power plugs in the card?