Today the day became worst when i format my windows 8 to installed windows 7, then i found i am not getting the dual boot option for Windows 10. I tried startup repair through windows 10 dvd but it is only showing win 7 for repair, no windows 10??
Both OS partitions were different C and D. I can see Windows 10 files are still in D drive.
How can i get back my Windows 10 again... i lost it somehow.....
Hi, from what I understand from other's experience of this, Win10 startup repair will not work in such a scenario.
Try this:
Dual Boot Repair Tool: Repair BCD Boot Configuration Data
and some have used this:
BCDEDIT - How to Use - Windows 7 Help Forums
..this link from above pages sounds pretty close to your scenario:
Windows OS missing from Boot Menu in a Multi-Boot Computer
Run the following commands at the command prompt.
diskpart
list volume NOTE: Note the volume letter where the Windows OS is installed.
exit
bcdboot X:\windows NOTE: Replace "X" with the volume letter of the Windows OS partition.
How to use the BCDboot command in Windows 7/8/10. -> link
The following is an example if you have a dual-boot system installed.
Quote
and thanks to others for helping me.. 
