Hello, & welcome to Tom's Hardware!
Need to know where the startup process is hanging. There are 6 phases.
POST, the startup screen (splash screen) boot manager (choice of multiboot, which may not be present), boot loader "OS is loading", Kernel phase "Windows starting", and the Logon phase (user logon). Finally if all goes well you see the Start Screen in Win-8
What is the last phase you see before you get a blank screen? I'm assuming by blue screen you don't mean a BSOD with white text, since Win-8 shows a different Stop Error screen.