My Macbook Pro won't boot up. I was installing some software for my lexmark printer and I also updated safari (I had noticed that I had an update available so I decided to go ahead and update). After that I went to reboot my machine and the white light near the front of the machine comes but the screen remains black. I've tried resetting the PMU by unplugging the power cord/battery and holding my power button and then putting everything back in and then turning it on. The only thing this accomplishes is now it will make the standard startup noise but the screen will remain black. I have a desktop where the graphics card crapped out which makes my display go black from time to time, does this have anything to do with it? Thanks for any help.