Half way into booting then black screen
Hello, I am having a problem when I try to boot into Yosemite after the installation. After the installation it restarts then I unplug my usb boot drive then it loads into the Yosemite Zone Menu. I see two apple logos and under the first one is the name of the hard drive where I installed Yosemite. The other apple logo says Recovery HD. I select my hard drive then halfway into loading it turns into a black screen. Oh yeah and when I was installing Yosemite I clicked customize and installed the npci=0x3000 kext. I also installed Yosemite without the kext and just left as is but it still did the same thing. When I boot into the installer I need to type /amd1 npci=0x3000 in order to load into the installation. I'm guessing it's a graphics card problem, I checked my graphics card compatibility and it is supported, since 10.8. it's the Sapphire Radeon 7950. Thank you for any replies!