Is your OSes installed as UEFI or MBR (legacy)? Or is it a hybrid setup?
Grub will override the Windows bootloader when you install it. If you want the Windows bootloader back you'll need a Windows install DVD/USB drive: http://superuser.com/questions/949219/how-to-fix-windows-10-boot-loader-from-windows
Personally, I install my OSes on separate SSDs. If I reinstall an OS I'll unplug the other OS SSDs so the bootloader won't override the others.
Thanks again.
My installation is on GPT partition . The HD is Toshiba, 2TB for Windows and 4TB for linux. In November when I ventured on the Ubuntu world for the first time, I have no problem with the installation of Ubuntu. In fact I ran 15.10 for several months, MC worked fine with the exception of my mkv movies not playing when directly in front of the PC. I was also able to watch movies via dlna.. across the room when MC is fired up under Ubuntu.
Then I had some corruption, I believe, so decided to start all over.
I did not experience any thing like Grub or so. I am surprise this is coming up.
I will wait until I hear from you again or other forum members.
I will try to reformat the 4TB partition, use this partiton for something else, then use an external stand alone WD 4TB box wipe out the contents and try to install Ubuntu on it again.
It looks like Windows 10 after been updated to whatever it is does not like to have other Os residing.
I must point this out. I can still boot from Windows no issues, all I do is go to the BIOS and point the boot menu to boot from Windows.
After Ubuntu install, it should give me a screen for me to make a choice. It does not do this anymore. All I see is this Grub ,then I have to type exit, or reboot.
Thanks
George