Hello everyone! Yesterday my friend bought Asus Prime z270-A Motherboard, i connected everything perfectly even i replaced thermal paste, booted up everything worked just like in dreams. So my friend decided that i should give him r7 graphics card which i think earlier on my other MOBO died somehow idk i wasn't sure if it was dead or not, i turned off pc, inserted GPU connected 6-pin connector put in HDMI cable and then when i tried to power it on it started booting then stopped and since then it won't boot or show RGB lights which are on MOBO, won't do anything PWR_LED is green, tried diff SUPPLY not working still.. He has Corsair 750w PSU, anyone know what should i do? 
Thanks for reply!

Thanks for reply!