I had problems installing nVidia drivers on my Aspire V-572G on Windows 7. Initially, I tried to use the downloaded GeForce Experience tool to auto-detect and download the correct driver. The tool ran, but came back with an error stating that "I needed to install an Intel Driver first." Ok, I thought, let's do that. I then downloaded the VGA Intel drivers from Acer's drivers page for my laptop. The drivers installed and I restarted the computer as suggested. My device manager now reported a working Intel Family HD Graphics controller and an unknown 3D Graphics Controller. However, when I tried to run the GeForce Experience tool again, I now received a message stating that "No compatible hardware was found.". The tool was not seeing any nVidia graphics card, since it was not registered in Windows as an Intel device (or so my hypothesis goes).
To fix the issue, I had to uninstall (not disable) the driver for the working Intel Graphics Controller and restart my computer. Next, I used the Intel utility to update the Intel graphics driver (instead of the driver from Acer's website, although the version number is identical, so I don't think this matters). However, I did not restart my computer. Instead, after installing the Intel Driver, but before my computer recognized the hardware for it, I again ran the nVidia tool. This time, it correctly found my GeForce 840m and after a few minutes installed the newest driver for it.