This, you see here, is a stop error. On normal desktop machines the actual background would be blue, giving it the popular name Blue Screen of Death. Take a look at the picture closely.
It says that Windows couldn't start because of a file missing (yada yada yada...), but as a suggestion for recovery it suggests you to enter you Windows installation disc to perform a recovery process. Now that just doesn't add up, because where would you connect a CD drive?
Now if you are on the fence side, this doesn't happen normally. According to Windows phone support you had to have been messing with your phone to cause something like this.
@winphonesupport I just played with flashing a little bit :)
— Johnny Ruokokoski (@rkkski) January 11, 2013
I wonder what you guys think of this.