Trying to upgrade to 16.04 i'm back to 15.10 but instalation fails too

[DarkLiz]

NVidia GeForce 750M with optimus not working in ubuntu 16.04. So i will back to 15.10 but the instalation fails...

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: ubiquity 2.21.37
ProcVersionSignature: Ubuntu 4.2.0-16.19-generic 4.2.3
Uname: Linux 4.2.0-16-generic x86_64
ApportVersion: 2.19.1-0ubuntu3
Architecture: amd64
CasperVersion: 1.365
Date: Mon May 2 21:54:22 2016
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/ubuntu.seed boot=casper only-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 15.10 "Wily Werewolf" - Release amd64 (20151021)
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)

[Phillip Susi (psusi)]

You experienced a number of segmentation faults during the install, which points to a likely hardware problem. Please run the "memtest" option from the bot menu and let it run for at least 15 minutes and see if it finds any errors with your ram.

[Launchpad Janitor (janitor)]

[Expired for grub-installer (Ubuntu) because there has been no activity for 60 days.]