Dualboot Windows Linux
If you want Debian Jessie on the same disk as Windows 8.1, here are the steps I had to go through: 1) Turn off Windows Fast Boot 2) You need to shrink the main Windows 8.1 partition. This can be tricky, as Windows expects a certain partition scheme to be used. Let me show you a diagram: [(Windows RE Tools)(EFI System Partition)(Microsoft Reserved Partition)(Windows 8.1)(Anything else)] You can use your favorite tool to edit these partitions. I prefer Gparted, but any good disk partitioning tool can handle this. Backup your Windows install first. Then, resize the Windows 8.1 partition so that you have enough space for another OS. I prefer to give Debian about 100 GB of space. 3) Download your Debian Jessie iso and put it on some media (CD/DVD/USB/(insert your preferred media here)). 4) Shut off Secure Boot and Fast Boot in the UEFI. DO NOT TURN ON LEGACY BOOTING (if your motherboard supports UEFI only booting without Secure Boot and Fast Boot on.) 5)