Looks like Intel vga driver V10.18.10.3308.02 and nVidia driver V9.18.13.2683 (or 326.83?) are posted on the
ASUS G55VW download site for Win8.1, so you may want to compare and consider upgrading (or downgrading?) to those versions to see if they make a difference or let us know which versions you are using?
If you don't use the ASUS approved vga drivers for your model, it can cause problems sometimes, so we want to check this too although you might only update the Intel vga driver first if you don't want to change your nVidia vga driver yet.