Here are a few tips for a clean upgrade to Windows 8.1.
First, with the Acer Recovery program to recover data to USB stick to carry out (thus one has all of the drivers in an emergency to a new installation)
Subsequently to the Acer Recovery Tools uninstall all Acer (Acer Identity Card can remain installed)
Next all installed software to uninstall the WLAN and BT software!
Delete all directories of Nvidia, in the Device Manager to uninstall the driver for NVIDIA (Software delete), as well as the BT software. Then again look for and delete the Windows Explorer by NVIDIA files and folders.
Call up the registry and delete all entries to NVidia, as far as possible.
Then clean up the registry with CCleaner.
Now the notebook should be almost "naked" with Windows 8.
The important thing is really the Nvidia drivers in the device manager, I have to again remove the driver, including Software and delete a few times.
Then in the Windows Store initiate the update to Windows 8.1.
Thereafter, from the Acer support site the required drivers for Windows 8.1 (not 8!) Be installed.
Good Luck :-)
