There were some similar questions but I really didn't understand.
I'm new to Linux and Ubuntu!
I had 4 drives:
C: NTFS (For Windows 8) D: EXT4 (For Ubuntu) E: NTFS (Persoanl Storgae) F: NTFS (Persoanl Storage)
I had Windows 8, Then I installed Ubuntu 15, Now my computer only boot Ubuntu, What should I do to restore Windows 8 boot.
When I installed Ubuntu, I deleted the D: drive then it became free space, then I add partition in installation page, then I set it as / and EXT4 and the drive for installation.