Burnt graphic card

I always believe that buying any hardware component for your computer is a bad idea, even though this time i have someone helping me out, it doesn't change the end result. So i bought a new graphic card which is a medium upgrade to my current graphic card i think, but in the end all the games i have install, all have problem with the new graphic card. Or maybe is the new graphic card has some comparability problem with my motherboard, so as my friend said.

So i went to change the graphic card at Ubi avenue today for a new one, maybe it is because the graphic card is spoilt that why i keep having problem with it working for my games. After replacing the graphic card and supposely everything worked quite ok, unit apparently certain game is run which somehow screwed up the graphic, the graphic card somehow burnt out, or i think it is burnt out because my computer cannot boot up with the graphic card attached. So end up i have to switch back to my old graphic card again, though somehow now i can't run company of heroes. So sian i have to go back and replace my graphic card again, and the worse thing is the place is only opened on weekdays during working hours. Remember that never change any components of pre-made computer, even when you want to upgrade.