Was fine previously. Can't dual boot now.

I wanted to reinstall ubuntu 16.10. It was working fine previously.But now, the grub error is continuously showing. Tried every trick on google. Still no luck.

ProblemType: Bug
DistroRelease: Ubuntu 16.10
Package: ubiquity 16.10.14
ProcVersionSignature: Ubuntu 4.8.0-22.24-generic 4.8.0
Uname: Linux 4.8.0-22-generic x86_64
ApportVersion: 2.20.3-0ubuntu8
Architecture: amd64
CasperVersion: 1.379
Date: Sun Jan 1 19:06:49 2017
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/ubuntu.seed boot=casper quiet splash ---
LiveMediaBuild: Ubuntu 16.10 "Yakkety Yak" - Release amd64 (20161012.2)
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)