Recently my windows refuses to load.

I press the power button, I hear the computer getting started, it lights up most the time (lights on the side).
My screen displays the Alienware logo with the balls rolling like it is loading something, like usually.
Then alienware logo stays here, and at this point windows would start but it doesn't.
Then it shuts down and my screen goes back to black.

I was under windows 8 and my computer wanted to install windows 8.1. I couldn't choose "remind me later" so I set it to 4hours. But I forgot about it and machinally turned my computer off.
I believe it is the source of the problem.

I've tried to press shift+F8 like I've read, I've checked the inside of my computer and I don't think there is any problems in there, I even took off all the dust.
Is this a known problem? I didn't find much information about it (if any at all).

I also tried to update some drivers before the update, but I can't remember which one. it was standart driver from windows. Some failed because my internet connection reset and they couldn't get downloaded. But could it really bug windows like that? It doesn't makes sense to me.

I hope someone can help me solve this problem,