Had to reisntall Windows 8.1 and couldn't boot to Ubuntu afterwards. then, i followed a tutorial to use Boot Repair. now, i see the boot screen to choose operating systems but the only option there is windows.
Windows is installed in a different drive than Ubuntu, so i didn't erase it from my computer. the Boot Repair report is here: http://paste.ubuntu.com/9937064/
Any help is appreciated.
Windows rewrote the partition table on sdb. Not quite sure why it modified sdb. Did you have sdb as default boot drive in BIOS? Windows puts it boot files on BIOS default not necessarily the drive you install to.
Since Windows does not properly see Linux, it does not correctly rewrite partition table. Your extended partition has a large gap from the start of the extended partition, and the start of swap nearer end of extended partition.
In many cases you can just use testdisk to restore the missing Linux partition and it will work or may need Boot-Repair just to restore grub to MBR.
Testdisk Instructions
http://www.cgsecurity.org/wiki/TestDisk_Step_By_Step
http://www.cgsecurity.org/wiki/Menu_Analyse
I would also copy Windows boot files bootmgr & /boot/BCD into sda and see it you can directly boot Windows from sda drive. If not run Windows repair to make sda work without sdb. And install grub to sdb so sdb works without sda. So not use auto fix in Boot-Repair as that just installs grub to all drives. You want advanced mode to choose which boot loader and which drive.
All depends on how you deal with it. You can use Windows (with it's master boot record) to give you a list of options: windows, linux, whatever else. In such a case you have to configure Windows boot manager with proper options - adding your linux on another disk)
You can actually boot from the Linux disk and there in grub select Windows or Linux, or something else (of course again having grub properly configured)
or - alternatively - all may depend on which disk you use to boot the system. If Windows - windows will start, if Linux - Linux will start.
Up to you.
