Hi there, I installed Windows 8 in parallel to OS X using bootcamp. For some reasons Windows 8 is not always booting correctly. Within a few sections (after selecting Windows 8 using the ALT key before) the screen turns black (off?) and nothing happens. I can more or less reproduce the issue all the time performing a cold start. Starting OS X first, followed by a restart and selecting Windows 8 next is normally more successful. I thought I will ask you guys first before contacting Apple... Specs of the iMac are in the Signature. Same behaviour using a fresh install of Windows 8 Pro and Pro N. I am using the latest Nvidia driver for the GTX 780M.