I took an existing dual booting disk from an UEFI Acer A5 notebook and swapped it into Acer One with BIOS. I can boot to Ubuntu 16.04 just fine but not into Windows 8.1.

:~$ sudo gdisk /dev/sda
GPT fdisk (gdisk) version 1.0.1

Partition table scan:

MBR: protective  
BSD: not present  
APM: not present  
GPT: present  

Found valid GPT with protective MBR; using GPT.

[sudo] password for: 
sda           465.8G            
├─sda4 ntfs   221.9G            Acer
├─sda2 vfat     300M            ESP
├─sda7 swap    20.9G [SWAP]     
├─sda5 ntfs     450M            
├─sda3          128M            
├─sda1 ntfs     400M            Recovery
├─sda8 ntfs    15.3G            Push Button Reset
└─sda6 ext4   206.5G /   
  • the new computer has EFI boot? what error do you get? Note: swapping computers will cause Windows Genuine Advantage to invalidate your key – ravery Jan 29 '18 at 8:37
  • The current computer has BIOS. Grub does not see the windows partition. I used super-grub-disk to get the computer booting first time. SGD sees the windows os but requires UEFI boot. – AJ-FIN Jan 29 '18 at 15:53
  • Disk /dev/sda: 465.8 GiB, 500107862016 bytes, 976773168 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes Disklabel type: gpt Device Start End Sectors Size Type /dev/sda1 2048 821247 819200 400M unknown /dev/sda2 821248 1435647 614400 300M EFI System /dev/sda3 1435648 1697791 262144 128M BIOS boot /dev/sda4 1697792 466947907 465250116 221.9G Microsoft basic data /dev/sda5 466948096 467869695 921600 450M Windows recovery – AJ-FIN Jan 29 '18 at 17:10
  • /dev/sda6 467869696 900894719 433025024 206.5G Linux filesystem /dev/sda7 900894720 944769023 43874304 20.9G Linux swap /dev/sda8 944769024 976773119 32004096 15.3G unknown – AJ-FIN Jan 29 '18 at 17:11

As you stated in comments, Windows is UEFI the computer is Legacy only.
This means that windows will not boot in this computer unless you reinstall windows in Legacy mode. The same is true of Grub that is why you had to use super grub disk to boot ubuntu.

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