Ok this could mean that either you need to update your GPU drivers which you can do through the Nvidia website, or if you have another GPU available, plug it into your motherboard and see if a signal is sent to your monitor. If there is a signal with another GPU then you have a bad GPU and should get it exchanged asap.
Edit: you should be using the top most GPU port to plug in your GPU. only use the lower ones if you are going to add a second GPU for SLI. Also if you use an alternate GPU to test on your build and it doesnt work either, the problem could be with your motherboard PCIe x16 slot.