Nouveau stopped my Acer V5-537G from crashing
Switching from Ubuntu 32-bit to 64-bit (14.04 and 15.04) I got problems with my Acer V5-537G freezing irrevocably, and only a hard restart would get it back to life again.
However by selecting the open source Nouveau driver for my Nvidia Geforce GT750M graphics card, the deep-freezes stopped. Now there are just temporary freeze-ups.