Computer Won't Get Past Black Screen

I'm having some serious troubles with my main PC, my gaming PC, and it's really messing things up for me. I was just parusing around like usual on my computer, it runs Windows 7, and I allowed it to download the usual updates and restart itself. When it shut down and began restarting, I notice that it loads up the logo, briefly flashes what I think is called a Bios Post page, and then goes to a page that is nothing but a blinking "__" sign. It does nothing here, won't continue, and I can't enter or do anything. It just endlessly blinks, before disappearing and the computer screen shows nothing but black.