I am newb in Ubuntu. Currently I am using an Acer V11 laptop with a pre-intalled Windows 8.1. I follow some guideline (http://www.everydaylinuxuser.com/2014/05/install-ubuntu-1404-alongside-windows.html) which successfully install Ubuntu 14.04 LTS alongside Windows 8.1 with UEFI enabled all the way throughout the installation and my current usage and a GRUB. But I got into some problem.
The dual boot mostly works fine as I am able to successfully boot into either one of the Windows 8.1 or Ubuntu when stating my laptop. However it ran into issue after I start the device and use Ubuntu for a while (2 hour for instance) and then restart it: If I press the restart from Ubuntu, the grub still shows and I am still able to choose the Windows Boot Manager. But the Windows loading process was stuck at the Acer Loading Screen and I am not able to see the standard circular Win8 loading progress bar. Does someone know why would this happens?