Gpu possibly not working right

So today I took my video card out to see how the intel hd 4000 graphics where just out of curiosity. I put my video card back in Plug the power cables in and every thing and try get get into windows 8 and it gets to the windows sign with the spiral as its booting then just goes blank. Idk what the hell is wrong. gpu is just what I think it is so this is where I'm posting. I have a sapphirregrade on 7950 FYI. please help 

Is the gpu not showing up as active in the windows device manager becase if so take out the card and go into the task manager using hd 4000 then uninstall the intel graphics driver,

re install the 7950 and its drivers and that should work! 

 

Hope it helped!