Hi, I'm from Argentina so excuse me if I can not express myself clearly. I have this problem with my GT740. When connect the gpu on the pcie slot and connect the monitor on the mini-hdmi and turn on the pc everything works fine. the problem appears when rebooting the pc after a clean drivers installation I get a black screen after windows 7 logo. I've been trying fix it for a month looking for people who solved this same problem on internet. But i couldn't fix my display problem, so i came here asking for some help. Here below I leave the specifications of my computer and my monitor. Tell me if you need to know anything else. 
 
Motherboard: Asrock N68-VS3 UCC
PSU: LNZ SX Series 550W
GPU: EVGA GT740 SC 2GB ddr3
Monitor: Samsung S23C350
 
Thanks for your attention. Hope we will solve it because I dont know what else to do.

i already tryied connecting the monitor on the mini-hdmi and dvi-d port, but it still not working. Actually i can get into the safe mode and everything works fine with the drivers installed but not in normal mode. when im with the gpu and open display configurations (on safe mode) it says that mi monitor has no adapter, but when im using the igpu its says that the adapter is the igpu. Later i will go test the gpu on a friend pc to see if its my pc or the gpu. thank you for answer. 

I tested the gpu on a gamer pc of a friend and it did the same, after installing the gpu drivers and restart the computer the screen goes black after windows logo. I tryied to find any solution but it wont work so i ask to the seller for a refund and its ok. tomorrow i will go to the post office to send it back. Thank you for you response.