My desktop did this after the last round of updates. It booted to a blank screen that looked like the brightness was turned down too low. What I found after much head scratching was that it had somehow corrupted the mouse drivers for my Razer mouse. The system would boot to a blank screen and if you tried to boot from the disk it would just sit there saying it was loading the files and would never change. The only clue was that it would make a high pitched sound from the motherboard speaker whenever you moved the mouse. I finally tried unplugging the mouse and the system booted up fine. I used an old mouse to get the latest drivers for the Razer and while the system would not let me uninstall the old drivers I deleted as many references to the Razer as I could find and loaded the new driver (which was the same version I had) and all is well again.