I never expected that an update could cause this damage, now I'll explain :
This morning I upgraded to Windows 8.1 and everything seemed normal startup.
At some point I realize , in Device Manager , the dedicated video card (AMD Radeon HD7670M ) is detected by another name ( amd hybrid ( blocked ) something, maybe).
So I decide to install the drivers that I had already used on windows 8 (version 13.3 beta3 ) but in the middle of the installation the screen goes black showing only the mouse pointer .
Look believing it was part of the procedure , but after about 15 minutes , I begin to think that something is not going to just the right way .
But I can not do anything , because even turning off the computer by removing the battery , the next time the screen remains black with only the mouse pointer visible.
I checked and discovered that holding down F5 as soon as you turn on the notebook , I can perform a system recovery .
Then restore to a few hours before (after , however, the upgrade to Windows 8.1) and everything is "normal."
I try to uninstall the video card from the system, and since it does not work either the control panel of the integrated video card ( HD 4000) , uninstall this one.
Restart, are recorded both video cards and are installed .
In the meantime, try with other drivers but no one solves the problem (some do not start with error messages and other force me to restore) .
At this point I think that there are no drivers that work for Windows 8.1, but is this possible?
Millions of people have already upgraded and I do not think that everyone has encountered this problem .
Unfortunately, I do not know why , I have no restore points that bring me back to Windows 8 , but I imagine it would be a bit complex as a " maneuver " .
I also tried with SW Update, but only a few small programs appear in the list and no drivers .
CPU-Z recognizes me two video cards with the same name "Graphic Device."
I hope to solve ?
Thank you all for the help