Your JournalErrors.txt seems to show a lot of nouveau kernel messages, which might be the problem...
Could you please try installing the proprietary nvidia driver? I think the latest Nvidia driver supporting your GPU is version 340: sudo apt install nvidia-340 ** Summary changed: - Severe graphical corruption in gnome-shell + Severe graphical corruption in gnome-shell with nouveau [Nvidia GeForce 8400M GS] ** No longer affects: ubuntu ** Changed in: gnome-shell (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1711936 Title: Severe graphical corruption in gnome-shell with nouveau [Nvidia GeForce 8400M GS] Status in gnome-shell package in Ubuntu: Incomplete Status in linux package in Ubuntu: Incomplete Bug description: When running gnome-shell on Ubuntu 17.10, text is visible only as white blocks (or sometimes not visible at all), and some graphics, such as the icons on the launcher menu, are corrupt. Only objects drawn by the gnome-shell and related programs seem to be affected. Software which is not part of the gnome-shell, such as LibreOffice, calculator, terminal, etc displays without corruption. --- ApportVersion: 2.20.6-0ubuntu6 Architecture: amd64 CurrentDesktop: ubuntu:GNOME DisplayManager: gdm3 DistroRelease: Ubuntu 17.10 GsettingsChanges: org.gnome.desktop.interface gtk-im-module 'gtk-im-context-simple' InstallationDate: Installed on 2017-08-20 (0 days ago) InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Alpha amd64 (20170818) Package: linux PackageArchitecture: amd64 ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash ProcVersionSignature: Ubuntu 4.12.0-11.12-generic 4.12.5 Tags: artful wayland-session Uname: Linux 4.12.0-11-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo _MarkForUpload: True To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1711936/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp