If this image brings back bad memories...
Or you get the "Black screen with a blinking cursor." That means there's a problem with the boot loader on your Windows install. The good news is that this doesn't mean the end of the world for your Windows install! The bad news is you're going to need to get your hands dirty in the command line. And there's also two paths you can take and I'll go through both.
Using a Recovery Environment
The only requirement is that yo