I have Ubuntu and Windows 8.1 in separated HDDs. My windows 8.1 pro installation is an upgraded windows 7 home premium one, so, it's installed as the same way as windows 7. now, I installed Ubuntu because my computer is having random power issues due to a 10 years old power supply. I have GRUB2 as the main bootloader (because windows always showing BSOD while in power issues). Now the power problems are fixed, but I can't boot windows 8.1 pro from GRUB2 (I can boot ubuntu of course), There's no errors to show or any BSOD, Just the windows logo without loading anything, I tried loading directly from de HDD in my Motherboard settings to windows 8.1 pro without using GRUB2 and worked without any problem. I think it is a problem with the windows 8 entry in the GRUB2 config, There's any way to fix this?