Diagnosis of a frozen splash screen?

So, last night my computer decided it didn't want to boot past the HP splash screen.

Usually there are several option commands at the bottom (press F2 for this, press F10 for that, etc) but in this case there were none. I turned the computer off and restarted, only to be greeted with the same thing. I unplugged my external hard drive, and all other peripherals that were plugged into the computer, with a similar result, only this time the function options were present at the bottom of the screen, however the computer was frozen. I restarted the computer again, and the options were available. I ran a quick scan of the hard disk, and everything passed and the computer booted as normal.

My question is: What could cause this, and how can i avoid it in the future? Could my computer be teetering on the brink of its final boot?

NOTE: The battery had completely depleted, I am guessing while the computer was still running. I ran out of the house and turned off my power strip, but forgot to shut down the computer.